Question Library
Browse, filter, and study verified past examination questions with step-by-step mathematical reasoning.
Searching 18,000+ Questions...
Sifting topics, KaTeX formulas & verified solutions
Showing 13756–13770 of 14893 verified questions
Sort by:
Mathematics
UTME / JAMB 1981
Indices, Logarithms & Surds
Solution
A micrometer is defined as one millionth of a millimeter. A length of 12,000 micrometres may be represented as
A
0.00012m
B
0.0000012m
C
0.000012m
D
0.00000012m
E
0.000000012m
medium Difficulty
Verified Correct Answer: Option C
Step-by-Step Mathematical Solution
1 UM = 10\(^{-6}\)mm
= 10\(^{-9}\)m
1.2 x 10\(^4\) x 10\(^{-9}\)m
= 1.2 x 10\(^{-5}\)m = (0.000012)m
Source: Myschool Past Questions Archive (Record #32572)
Mathematics
UTME / JAMB 1981
Plane Geometry, Polygons & Circle Theorems
Solution
In one and a half hours, the minute hand of a clock rotates through an angle of
A
90o
B
180o
C
640o
D
450o
E
540o
medium Difficulty
Verified Correct Answer: Option E
Step-by-Step Mathematical Solution
1 hr, = 60 mins, 60 mins = 360o
30 mins = \(\frac{360^o}{1}\) c \(\frac{30}{60}\)
= 180o
90 mins = 360 + 180o
= 540o
Source: Myschool Past Questions Archive (Record #32575)
Mathematics
UTME / JAMB 1981
Indices, Logarithms & Surds
Solution
Simplify \(\frac{\sqrt{2}}{\sqrt{3} - \sqrt{2}}\) - \(\frac{\sqrt{3} - \sqrt{2}}{\sqrt{3} + \sqrt{2}}\)
A
2\(\sqrt{2} - \sqrt{3}\)
B
3(\(\sqrt{6}\) - 1)
C
\(\sqrt{6}\) - 3
D
-\(\frac{1}{2}\)
E
\(\frac{-\sqrt{3}}{\sqrt{2} - \sqrt{2}}\)
medium Difficulty
Verified Correct Answer: Option B
Step-by-Step Mathematical Solution
\(\frac{\sqrt{2}}{\sqrt{3} - \sqrt{2}}\) - \(\frac{\sqrt{3} - \sqrt{2}}{\sqrt{3} + \sqrt{2}}\)
\(\frac{\sqrt{2}}{\sqrt{3} - \sqrt{2}}\) = \(\frac{\sqrt{2}}{\sqrt{3}}\) - \(\frac{\sqrt{3}}{\sqrt{2}}\)
\(\frac{\sqrt{3} + \sqrt{2}}{3 + \sqrt{2}}\) = \(\sqrt{6}\) + 2
\(\frac{\sqrt{3} - \sqrt{2}}{\sqrt{3} + \sqrt{2}}\) = \(\frac{\sqrt{3} - \sqrt{2}}{\sqrt{3} + \sqrt{2}}\) x \(\frac{\sqrt{3} - \sqrt{2}}{\sqrt{3} - \sqrt{2}}\)
= 5 - 2\(\sqrt{6}\)
\(\sqrt{6}\) + 2 - (5 - 2 \(\sqrt{6}\)) = \(\sqrt{6}\) + 2 - 5 + 2\(\sqrt{6}\)
= 3\(\sqrt{6}\) - 3
= 3(\(\sqrt{6}\) - 1)
Source: Myschool Past Questions Archive (Record #32582)
Mathematics
UTME / JAMB 1981
Linear, Simultaneous & Quadratic Equations
Solution
Solve \(\frac{1}{x + 1}\) - \(\frac{1}{x + 3}\) = \(\frac{1}{4}\)
A
x = -1 or 3
B
x = 1 or 3
C
x = 1 or -5
D
x = -1 or 5
E
x = -1 or -3
medium Difficulty
Verified Correct Answer: Option C
Step-by-Step Mathematical Solution
\(\frac{1}{x + 1}\) - \(\frac{1}{x + 3}\) = \(\frac{1}{4}\)
\(\frac{x + 3 - x - 1}{(x + 1)(x + 3)}\) = \(\frac{1}{4}\)
\(\frac{2}{x^2 + 4x + 3}\) = \(\frac{1}{4}\)
= x2 + 4x + 3 = 8
x2 + 4x - 5 = 0
= (x - 1)(x + 5) = 0
x = 1 or -5
Source: Myschool Past Questions Archive (Record #32583)
Mathematics
UTME / JAMB 1981
Plane Geometry, Polygons & Circle Theorems
Solution
In \(\bigtriangleup\)XYZ, XY = 3cm, XZ = 5cm and YZ = 7cm. If the bisector of XYZ meets XZ at W, what is the length of XW?
A
1.5cm
B
2.5cm
C
3cm
D
4cm
E
None of the above
medium Difficulty
Verified Correct Answer: Option A
Step-by-Step Mathematical Solution
Let XW = a, a :7
\(\frac{a}{5 - a}\) = \(\frac{3}{7}\)
7a = 15 - 3a
10a = 15
a = \(\frac{15}{10}\)
= \(\frac{3}{2}\)
= 1.5cm
Source: Myschool Past Questions Archive (Record #32584)
Mathematics
UTME / JAMB 1981
Indices, Logarithms & Surds
Solution
If \(\log_{2} y = 3 - \log_{2} x^{\frac{3}{2}}\), find y when x = 4.
A
8
B
\(\sqrt{65}\)
C
4\(\sqrt{2}\)
D
3
E
1
medium Difficulty
Verified Correct Answer: Option E
Step-by-Step Mathematical Solution
\(\log_{2} y = 3 - \log_{2} x^{\frac{3}{2}}\)
When x = 4,
\(\log_{2} y = 3 - \log_{2} 4^{\frac{3}{2}}\)
\(\log_{2} y = 3 - \log_{2} 2^{3}\)
\(\log_{2} y = 3 - 3 \log_{2} 2 = 3 - 3 = 0\)
\(\log_{2} y = 0 \implies y = 2^{0} = 1\)
Source: Myschool Past Questions Archive (Record #32585)
Mathematics
UTME / JAMB 1981
Indices, Logarithms & Surds
Solution
Given that 10\(^x\) = 0.2 and log\(_{10}\)2 = 0.3010, find x
A
-1.3010
B
-0.6990
C
0.6990
D
1.3010
E
0.02
medium Difficulty
Verified Correct Answer: Option B
Step-by-Step Mathematical Solution
Given that log\(_{10}\)2 = 0.3010, If 10\(^x\) = 0.2
log\(_{10}\)10\(^x\) = log\(_{10}\) 0.2 = x = log\(_{10}\)0.2
But 0.2 = 2 x 10\(^{-1}\), so log\(_{10}\)0.2 = log\(_{10}(2 \times 10^{-1})\), x = log\(_{10}\)2 + log\(_{10}\)10\(^{-1}\)
x = 0.3010 - 1
x = - 0.6990
Source: Myschool Past Questions Archive (Record #32586)
Mathematics
UTME / JAMB 1981
Linear, Simultaneous & Quadratic Equations
Solution
Two cars X and Y start at the same point and travel towards a point P which is 150km away. If the average speed of Y is 60km per hour and x arrives at P 25 minutes earlier than Y. What is the average speed of X?
A
51\(\frac{3}{7}\)km per hour
B
72km per hour
C
37\(\frac{1}{2}\) km per hour
D
66km per hour
E
75km per hour
medium Difficulty
Verified Correct Answer: Option B
Step-by-Step Mathematical Solution
Distance travelled by both x and y = 150 km.
Speed of y = 60km per hour, Time = \(\frac{dist.}{Speed}\)
Time spent by y = \(\frac{150}{60}\)
= 2\(\frac{3}{6}\)hrs
= \(\frac{1}{2}\) hrs
if x arrived at p 25 minutes earlier than y, then time spent by x = 2 hour 5 mins
= 125 mins
x average speed = \(\frac{150}{125}\) x \(\frac{60}{1}\)
= \(\frac{9000}{125}\)
= 72 km\hr
Source: Myschool Past Questions Archive (Record #32587)
Mathematics
UTME / JAMB 1981
Indices, Logarithms & Surds
Solution
simplify \(\frac{6^{2n + 1} \times 9^n \times 4^{2n}}{18^n \times 2^n \times 12^{2n}}\)
A
32n
B
3 x 23n - 1
C
2n
D
6
E
1
medium Difficulty
Verified Correct Answer: Option D
Step-by-Step Mathematical Solution
\(\frac{6^{2n + 1} \times 9^n \times 4^{2n}}{18^n \times 2^n \times 12^{2n}}\) = \(\frac{(2 \times 3^{2n + 1} \times 3^{2n}) \times 2^{4n}}{(2 \times 9)^n \times 2^n \times (6 \times 2^{2n})}\)
= \(\frac{(2^{2n + 1} \times 3^{2n + 1}) \times 3^{2n} \times 2^{4n}}{2^n \times 3^{2n} \times 2^n \times 2^{4n} \times 3^{2n}}\)
= \(\frac{2^{2n} + 1 + 4^n \times 3^{2n} + 1 + 2^n}{2^{n + n + 4n} \times 3^{2n + 4n} \times 3^{2n + 2n}}\)
= \(\frac{2^{6n + 1} \times 3^{4n + 1}}{2^{6n} x 3^{4n}}\)
= 26n + 1 - 6n x 34n + 1 - 4n
2 x 3 = 6
Source: Myschool Past Questions Archive (Record #32588)
Mathematics
UTME / JAMB 1981
Number Bases & Modular Arithmetic
Solution
The number 25 when converted from the tens and units base to the binary base (base two) is one of the following
A
10011
B
111011
C
111000
D
11001
E
110011
medium Difficulty
Verified Correct Answer: Option D
Step-by-Step Mathematical Solution
\(\begin{array}{c|c} 2 & 25\\2 & 12 R 1\\2 & 6 R 0\\2 & 3 R 0\\2 & 1 R 1\\2&0 R 1\end{array}\)
= (11001)
Source: Myschool Past Questions Archive (Record #32589)
Mathematics
UTME / JAMB 1981
Indices, Logarithms & Surds
Solution
Evaluate \(\frac{6.3 \times 10^5}{8.1 \times 10^3}\) to 3 significant fiqures
A
77.80
B
778.0
C
7.870
D
8.770
E
88.70
medium Difficulty
Verified Correct Answer: Option A
Step-by-Step Mathematical Solution
\(\frac{6.3 \times 10^5}{8.1 \times 10^3}\)
\(\frac{7}{9} \times 10^{2}\)
= \(0.77778 \times 10^{2}\)
= \(77.778 \approxeq 77.80\)
Source: Myschool Past Questions Archive (Record #32590)
Mathematics
UTME / JAMB 1981
Indices, Logarithms & Surds
Solution
The positive root of t in the following equation, 4t2 + 7t - 1 = 0, correct to 4 places of decimal, is
A
1.0622
B
10.6225
C
0.1328
D
0.3218
E
2.0132
medium Difficulty
Verified Correct Answer: Option C
Step-by-Step Mathematical Solution
\(4t^{2} + 7t - 1 = 0\)
Using a = 4, b = 7, c = -1.
\(x = \frac{-b \pm \sqrt{b^{2} - 4ac}}{2a}\)
= \(\frac{-7 \pm \sqrt{7^{2} - 4(4)(-1)}}{2(4)}\)
= \(\frac{-7 \pm \sqrt{49 + 16}}{8}\)
= \(\frac{-7 \pm \sqrt{65}}{8}\)
= \(\frac{-7 \pm 8.0623}{8}\)
The positive answer = \(\frac{-7 + 8.0623}{8} = \frac{1.0623}{8}\)
\(\approxeq 0.1328\) (4 decimal place)
Source: Myschool Past Questions Archive (Record #32591)
Mathematics
UTME / JAMB 1981
Plane Geometry, Polygons & Circle Theorems
Solution
The difference between the length and width of a rectangle is 6cm and the area is 135cm2. What is the length?
A
25cm
B
18cm
C
15cm
D
24cm
E
27cm
medium Difficulty
Verified Correct Answer: Option C
Step-by-Step Mathematical Solution
Area = L x B
L - B = 6
L = 6 + B
area = 135
B(6 + B) = B\(^2\) + 6B - 135 = 0
(B - 9)(B + 15) = 0
B = 9 or - 15
L = 6 + 9 = 15
Source: Myschool Past Questions Archive (Record #32592)
Mathematics
UTME / JAMB 1981
Mensuration (Areas, Perimeters & Volumes)
Solution
The area of a circular plate is one-sixteenth the surface area of a ball of a ball, If the area of the plate is given as P cm2, then the radius of the ball is
A
\(\frac{2P}{\pi}\)
B
\(\frac{P}{\sqrt{\pi}}\)
C
\(\frac{P}{\sqrt{2\pi}}\)
D
2\(\frac{P}{\pi}\)
medium Difficulty
Verified Correct Answer: Option D
Step-by-Step Mathematical Solution
Surface area of a sphere = 4\(\pi\)r2
\(\frac{1}{16}\) of 4\(\pi\)r2
= \(\frac{\pi r^2}{4}\)
P = \(\frac{\pi r^2}{4}\)
r = 2\(\frac{P}{\pi}\)
Source: Myschool Past Questions Archive (Record #32593)
Mathematics
UTME / JAMB 1981
Trigonometry, Elevation & Bearings
Solution
Show that \(\frac{\sin 2x}{1 + \cos x}\) + \(\frac{sin2 x}{1 - cos x}\) is
A
sin x
B
cos2x
C
2
D
3
medium Difficulty
Verified Correct Answer: Option C
Step-by-Step Mathematical Solution
\(\frac{\sin^{2} x}{1 + \cos x} + \frac{\sin^{2} x}{1 - \cos x}\)
\(\frac{\sin^{2} x (1 - \cos x) + \sin^{2} x (1 + \cos x)}{1 - \cos^{2} x}\)
= \(\frac{\sin^{2} x - \cos x \sin^{2} x + \sin^{2} x + \sin^{2} x \cos x}{\sin^{2} x}\)
(Note: \(\sin^{2} x + \cos^{2} x = 1\)).
= \(\frac{2 \sin^{2} x}{\sin^{2} x}\)
= 2.
Source: Myschool Past Questions Archive (Record #32594)