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: The average age of 3 boys is 15 years and their ages are in the proportion 1:2:3. The age of the youngest boy is?

 Option A: 10 years

 Option B: 12 years

 Option C: 15 years

 Option D: 18 years

 Option E: 7.5 years
Option E

Question: If the least common multiple of two prime numbers x and y is 10, where x > y, then the value of 2x + y is

 Option A: 7

 Option B: 9

 Option C: 11

 Option D: 12

 Option E: 21
Option D

Question: The difference between compound and simple interest on a certain sum of money for 3 years at 6 2/3% p.a is Rs.184. Find the sum?

 Option A: 22887

 Option B: 28779

 Option C: 27677

 Option D: 13500

 Option E: 17971

Option D