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.

[EX Q]: Question: A grocer purchased a quantity of bananas at 3 pounds for $0.50 and sold the entire quantity at 4 pounds for $1.00. How many pounds did the grocer purchase if the profit from selling the bananas was $6.00?

 Option A:  72

 Option B:  60

 Option C:  90

 Option D:  120

 Option E:  240
[EX A]: Option A

[EX Q]: Question: The ratio between the speeds of two trains is 7 : 8. If the second train runs 400 kms in 4 hours, then the speed of the first train is:

 Option A: 70 km/hr

 Option B: 75 km/hr

 Option C: 84 km/hr

 Option D: 87.5 km/hr

 Option E: 88.5 km/hr
[EX A]: Option D

[EX Q]: 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
[EX A]:
Option D