You are given a math word problem and you are supposed to make use of mathematical concepts like probability, combinatorics, linear equations, sequences/series, or simple operators like addition, subtraction, division, or multiplication to answer the given question. Choose the best option from the 5 given options and report that option.

Question: If one-third of one-fourth of a number is 15, then three-tenth of that number is

 Option A: 35

 Option B: 36

 Option C: 45

 Option D: 54

 Option E: 57
Option D

Question: The total of the ages of Amar, Akbar and Anthony is 30 years. What was the total of their ages three years ago ?

 Option A: 20 years

 Option B: 28 years

 Option C: 71 years

 Option D: 21 years

 Option E: 31 years
Option D

Question: A circular mat with diameter 7 inches is placed on a square tabletop, each of whose sides is 8 inches long. Which of the following is closest to the fraction of the tabletop covered by the mat?

 Option A: 6/7

 Option B: 4/9

 Option C: 5/2

 Option D: 5/3

 Option E: 1/7

Option C