Question

Alex's friends have collected 180 gold coins to give to charity. Alex decides he wants to donate some gold coins also, so he adds some gold coins to the 180 that his friends have already collected. Alex decides he must donate an integer number of coins which will make up between 10% and 20%, inclusive, of the total number of gold coins donated. What is the difference between the maximum number of gold coins Alex can donate and the minimum number of gold coins he can donate?

Answer 1

9/10=180/x
x=200

8/10=180/x
(180*10)/8
(180*5)/4
x= 225

225-200=25
Answer: 25
I THINK