of 3 numbers , the third is twice the second and the second is 4 times the first . if their average is 78 , the smallest of the 3 numbers is :	Choose the correct choice from the following options
A) 18  B) 19  C) 20  D) 21  E) 22

Rationale: explanation : let first number be x . so , 2 nd no . = 4 x & 3 rd no . = 8 x . so , x + 4 x + 8 x = 78 × 3 = 234 . 13 x = 234 x = 234 / 13 hence , smallest number x = 18 . answer : a
Answer: A