Question

7. Write equation for the following:
() A number exceeds its one-fifth by 20. Find the number,
(11) Find the number which when multiplied by 17 increases by 640.​

Answer 1

Solution :

a) The required number is 25 .

b) The required number is 40.

Step by step Explanation :

a) We have to find the number

Let the number be x

According to the Question

A number exceeds its one-fifth by 20.Then ,

$\sf\implies\:x-\dfrac{x}{5}=20$

$\sf\implies\:\dfrac{5x-x}{5}=20$

$\sf\implies\:\dfrac{4x}{5}=20$

$\sf\implies\:4x=20\times5$

$\sf\implies\:4x=100$

$\sf\implies\:x=\dfrac{100}{4}$

$\sf\implies\:x=25$

Therefore, the number is 25 .

b) We have to find the number

Let the number be x

According to the Question :

The number which when multiplied by 17 increases by 640.Then ,

$\sf\implies\:17x=x+640$

$\sf\implies\:17x-x=640$

$\sf\implies\:16x=640$

$\sf\implies\:x=\dfrac{640}{16}$

$\sf\implies\:x=40$

Therefore, the number is 40.

Answer 2

$\huge{\orange{\underline{\underline{\tt{SoluTion:}}}}}$

1. Let's

The Unknown Number be 'x'

Given, A number exceeds its one-fifth by 20.

According To The Sum

$→\;{\bf{x-\frac{x}{5} = 20}}$

Take the LCM is '5'.

$→\;{\bf{\frac{5x-x}{5} = 20}}$

$→\;{\bf{\frac{4x}{5} = 20}}$

$→\;{\bf{4x = 20×5}}$

$→\;{\bf{4x = 100}}$

$→\;{\bf{x = {\cancel{\frac{100}{4}}}}}$

$➝\;{\sf{x = 25}}$

.:. The Required Number is $\fbox\red{25}$

______________________

2. Let's

The Unknown Number be 'y'

Given, The number when multiplied by 17 increases by 640.

According To The Sum

$→\;{\bf{17x = x+640}}$

$→\;{\bf{17x-x = 640}}$

$→\;{\bf{16x = 640}}$

$→\;{\bf{x = {\cancel{\frac{640}{16}}}}}$

$➝\;{\sf{x = 40}}$

.:. The Required Number is $\fbox\green{40}$

Hope It Helps You ✌️