Question

A number is increased by 50% and then decreased by 50% resulting in 780 the no is

Answer 1

Answer:

Step-by-step explanation:

Answer 2

Given :

There are a number is increased by 50% and then decreased by 50% resulting in 780.

To Find:

What is that number?

Solution:

Let that number are:

Number = A

Here is first increase and then decrease. Then this can be solve by formula:

$\mathbf{A\left ( 1+\dfrac{R_{1}}{100} \right )\left (1-\dfrac{R_{2}}{100} \right ) =B}$       ...1)

Where:

A = unknown

In first bracket positive sign is for increase in percentage while negative sign in second bracket is decrease in percentage:

B = Final number = 780

On putting respective value in equation 1):

$\mathbf{A\left ( 1+\dfrac{50}{100} \right )\left (1-\dfrac{50}{100} \right ) =780}$

$\mathbf{A\left ( 1+\dfrac{1}{2} \right )\left (1-\dfrac{1}{2} \right ) =780}$

$\mathbf{A\times \dfrac{3}{2} \times \dfrac{1}{2}=780}$

$\mathbf{A =\dfrac{780\times 2\times 2}{3}}$

A = 1040

Means 1040 is that number which first increased by 50% and then decreased by 50%.