Question

Average of 3 numbers is 117, 1st = 3 x 2nd, 2nd = 2 x 3rd, find the difference of 2^nd and third number?

1. 30
2. 25
3. 19
4. 39

Answer 1

Correct Answer - Option 4 : 39

Given:

Average of 3 numbers = 117

1^st number = 3 x 2^nd number

2^nd number = 2 x 3^rd number

Concept:

Average = Sum of observations/Number of observations

Calculation:

Let, 3^rd number = x

second number = 2x

first number = 6x

Total of 3 numbers = (117 × 3) = 351

According to the question,

⇒x + 2x + 6x = 351

⇒  9x = 351

⇒ x = 39

∴  3^rd number = x = 39

∴ required difference = (78 ─ 39) = 39