Question

Jarek had 75 donuts and cookies. After giving away 1/5 of his donuts and 20 cookies, he had equal number of donuts and cookies. How many donuts did Jarek have in the beginning?

Answer 1

In the beginning Jarek had 80 cookies.

Explanation:

Number of donuts Jarek had = 75

amount of donuts Jarek gives away = 1/5

amount of Cookies Jarek gives away =20

To Find:

Number of Donuts Jarek had in the beginning = ?

Solution:

Let the number of Donuts Jarek had in the beginning be x

then

The number of donuts Jarek has after giving 1/5th of the donuts = the number of cookies he has after giving away 20 cookies

The number of donuts Jarek has after giving 1/5th of the donuts

=>
`75 - (1)/(5)\text{th of }75`

=>
`75 - (1)/(5)* 75`

=>
`75 - (75)/(5)`

=>
`75 - 15`

=> 60--------------------------------------------(1)

The number of cookies he has after giving away 20 cookies

=> x - 20-----------------------------------------(2)

Equationg (1) and (2)

60 = x-20

x = 60 +20

x = 80