Answer:
$22.50
Step-by-step explanation
90 is 80% (4/5) of what number (x)? So you do 90 times 100 = 9000 and 80 times x is 80x and then 9000 divided by 80 is 112.5 so she had 112.5 to begin with but she spent 1/5 so 112.5 divided by 5 is 22.5 so 1 fifth is 22.5
