Mark owes his sister $15. He earned $20. He gave 1/5 of his earnings to a local charity and then he paid his sister. Does Mark have enough to repay his sister the full amount? Why or why not?

Yes, Mark has $16 left and only has to pay his sister $15.

Step-by-step explanation:

1/5=x/20

use cross multiplication to find (x), which represents 20% of 20.

x/20=1/5 (cross multiply)

20=5x (divide by 5 on both sides)

x=4

This tells you that Mark gave $4 to the local charity.

20-4=16

Subtracting 4 from his original amount, he now has $16 left.

Answer: yes

Step-by-step explanation:

Mark gave 1/5 of 20 = $4 to local charity. He has $16 left. He paid his sister $15. He still has $16 - $15 = $1 left