Out of two numbers, the first number is three-fourth of the second number. If the average of the reciprocal of the two numbers is 7/48, then the first number is:
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 6.
Given:
The first number is three-fourth of the second number. If the average of the reciprocal of the two numbers is 7/48
Formula used:
Average = Sum of observation/number of observations ---- (1)
Calculations:
Let the second number be 40x
First number = (3/4) × 40 = 30x
Total sum of the reciprocal of the two numbers = (1/40x) + (1/30x) = (7/120)x
Average of the reciprocal of the two numbers = (7x/120)/2 = 7x/240
According to the question,
⇒ 7x/240 = 7/48
⇒ x = 1/5
First number = 30x = 30/5 = 6