Question

If 2.8, 7, 12 and x are in proportion then x = ……………….. 

A) 20 

B) 31 

C) 30 

D) 40

Answer 1

Correct option is (C) 30

Given that 2.8, 7, 12 and x are in proportion.

\(\therefore\) 2.8 : 7 = 12 : x

\(\Rightarrow\) \(\frac{2.8}7=\frac{12}x\)

\(\Rightarrow\) \(x=12\times\frac7{2.8}=\frac{12}{0.4}=\frac{120}4\) = 30

Answer 2

Correct option is  C) 30