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:

Correct option is C

Given:

X is the third proportional to 20 and Y

Y is the sum of the first three prime numbers

Concept Used:

If a : b = b : c, then c is the third proportional to a and b

So, c = $$\frac{b^2}{a}$$​​

Solution:

First three prime numbers: 2, 3, 5

Y = 2 + 3 + 5 = 10

X = $$\frac{Y^2}{20} = \frac{10^2}{20} = \frac{100}{20}$$​ = 5