One-third of the sum of two numbers is 12, twice their difference is 12. Find the numbers.
A
22 and 14
B
20 and 16
C
21 and 15
D
23 and 13
Verified Correct Answer: C.
Step-by-Step Mathematical Solution
Let the two numbers be x and y
\(\frac{1}{3}( x + y) = 12\)
then x + y = 36 ..........i
2( x - y) = 12
x - y = 6 ............ii
add equations i and ii
2x = 42
x = 21, put x = 21 into equation i
x + y = 36
21 + y = 36
y = 36 - 21 = 15
therefore the numbers are 21 and 15
Source: WAEC / JAMB / NECO Classroom Archive (Record #68974)