Answer:
Step-by-step explanation:
Let her total earnings be $m
Rent = m/4
Food = m/5
Let the among left be X
: m/4 + m/5 + X = m
Multiply each term by 20
5m + 4m + 20X = 20m
Collecting like terms
20X = 20m - 5m - 4m
20X = 11m
X = 11m/20
Amount left = $11m/20