Given that X is the third proportional of 20 and Y, if Y is the sum of the first three prime numbers, then the value of X is:
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 5 .
First three prime numbers = 2, 3, 5
Y = 2 + 3 + 5 = 10
Third proportional means → 20 : Y = Y : X
X = (Y × Y) ÷ 20
= 10 × 10 ÷ 20
= 100 ÷ 20
= 5