Question

A number is doubled and 9 is added.If resultant is trebled it becomes 75.What is that number?
A) 10, B) 14, C) 8, D) 12

Answer 1

Given :

A number is doubled and 9 is added. If the resultant is trebled it becomes 75.

To find :

The original number.

Solution :

Let the number is x

It is doubled = 2x

Then added 9 = 2x+9

Resultant is tripled. = 3(2x+9)

According to the given question :

=> 3(2x+9) = 75

=> 6x + 27 = 75

=> 6x = 75 - 27

=> 6x = 48

=> x = 48/6 = 8.

=> x = 8

Hence, the original number is 8.

Answer 2

Answer:

Option C - 8

Step-by-step explanation:

Given : A number is doubled and 9 is added. If resultant is tripled it becomes 75.

To find : What is that number?

Solution :

Let the required number be 'x',  

A number is doubled and 9 is added.

i.e. $2x+9$

If resultant is tripled it becomes 75.

i.e. $3(2x+9)=75$

Solve the equation,

$6x+27=75$

$6x=75-27$

$6x=48$

$x=\frac{48}{6}$

$x=8$

Therefore, The required number is 8.

So, Option C is correct.