Question

Solve the problem

3:78::5:?

A)120
B)125
C)135
D)115

Answer 1

Your options don't have the correct answer
The correct answer is 130

Answer 2

Given:

3:78::5:?

To find:

Missing number

Solution:

3:78::5:?

Let x be the missing number of the proportion

We know that

When two ratios are equal then we say that the ratios are in proportion.

a:b::c:d

a/b=c/d

Using the property

$\frac{3}{78}=\frac{5}{x}$

Using cross multiplication

$3x=5\times 78$

$x=\frac{5\times 78}{3}=130$

Hence, the missing number in the proportion should be 130.