The mean of a set of six numbers is 60. If the mean of the first five is 50, find the sixth number in the set.
A
105
B
100
C
95
D
110
Verified Correct Answer: D.
Step-by-Step Mathematical Solution
Let the sum of the first five numbers and the sixth number be x and t respectively.
\(\frac{x + t}{6} = 60 \implies x + t = 360\)
\(\frac{x}{5} = 50 \implies x = 250\)
\(\therefore t = 360 - 250 = 110\)
Source: Myschool Past Questions Archive (Record #3395)