Question

A number is tripled and added 3, if the resultant is doubled, it becomes 30. What is the number?

Answer 1

2(3x + 3) = 30

6x + 6 = 30

6x = 24

x = 4

Answer 2

Answer :

Let the unknown no. be equal to x.

Let's do step by step,

Firstly the no. is tripled :-

3x

Secondly, 3 is added to the tripled no. :-

3x + 3

Now, the result is doubled :-

2( 3x + 3 )

Given,

After being doubled it equals to 30

Now, forming a equation :-

2( 3x + 3 ) = 30

Now, solving this linear equation in one variable i.e x using transposition :-

Taking 2 to RHS :-

3x + 3 = 30/2

3x + 3 = 15

Taking 3 to RHS :-

3x = 15 - 3

3x = 12

Taking 3 ( coefficient of x ) to RHS :-

x = 12/3

x = 4

Therefore, the required unknown no. is 4 .