Question

Thrice of a number, added to half itself gives 21 . Find the number​

Answer 1

let the number be x

3x+x/2 = 21

7x/2 = 21

7x = 21×2

x = 21×2/7

x = 6

hope my answer helps you !

Answer 2

Answer:

Required number is $6 \frac{5}{6}$

Step-by-step explanation:

Given,thirce of a number added to half itself gives 21.

Let the number be x.

Now thrice of the number means thrice of x.

So,thrice of x =x is multiplied by 3$= 3 \times x = 3x$

Now it is added to half.

So the number becomes $3x + \frac{1}{2}$

Given it is equal to 21.

According to question,

$3x + \frac{1}{2} = 21$

we are separating variable and constant part,

$3x = 21 - \frac{1}{2}$

Here $\frac{1}{2}$

is subtracting from 21.

$3x = \frac{21 \times 2 - 1}{2} = \frac{42 - 1}{2} = \frac{41}{2}$

So,$3x = \frac{41}{2}$

By cross multiplication,

$3x \times 2 = 41$

$6x = 41$

$x = \frac{41}{6}$

Here 41 is dividing by 6.

$x = 6 \frac{5}{6}$

Therefore the number is $6 \frac{5}{6}$