Question

Madhurima thought of a number,doubled it and added 20 to it. on dividing the result number by 25 she gets 4. what is the nunber​

Answer 1

Given:

A number = x which was

• Doubled = 2x
• Added to 20 = 2x + 20
• Divide by 25 = $\dfrac{2x + 20}{25}$

The result is 4.

∴ So the equation will be $\dfrac{2x + 20}{25} = 4$.

What To Find:

Find the value of x.

Solution:

$\dfrac{2x + 20}{25} = 4$

Use cross multiplication,

⇒ 2x + 20 = 4(25)

Solve the brackets in RHS,

⇒ 2x + 20 = 100

Take 20 to RHS,

⇒ 2x = 100 - 20

Subtract 20 from 100,

⇒ 2x = 80

Take 2 to LHS,

⇒ x = $\dfrac{80}{2}$

Divide 80 by 2,

⇒ x = 40

∴ Thus, the number was 40.

To verify:

$\dfrac{2x + 20}{25} = 4$

Substitute the value of x,

⇒ $\dfrac{2(40) + 20}{25} = 4$

Solve the brackets,

⇒ $\dfrac{80 + 20}{25} = 4$

Add the numerator,

⇒ $\dfrac{100}{25} = 4$

Divide 100 by 25,

⇒ 4 = 4

∴ LHS = RHS

∴ Hence, verified.