A student has some $20 and $5 bills in his wallet. In total, he has 11 bills that add up to $115. How many of each type of bill does he have, using the variable “n” for the amount of $5 bills?

Question

I can only use the variable “n” for the amount of $5 bills, and no other variables- I just need some help ahaha

Answer 1

5n + 20x = 115

n+x = 11

5n +5x = 55

15x =60

x = 4 20 dollar bills

n = 7 5 dollar bills

or if you want to use only n and no other variable like x then

5n +20(11-n) = 115

5n-20n = 115 -220

15n = 105

n = 105/15 = 7 five dollar bills

11-n = 4 twenty dollar bills