If 0.75 : x :: 2.5 : 8, then the value of x will be equal to:

Correct option is D

Given: 

0.75 : x :: 2.5 : 8

Formula used:

In the case of a proportion, the product of the extreme terms is equal to the product of the middle terms. 

Solution:

0.75 : x :: 2.5 : 8

=> 2.5x = 0.75 × 8

=> x = 2.4

Thus, the required value of x is 2.4.