Answer:
3 1/3 minutes or 3 minutes 20 seconds
Step-by-step explanation:
We can use ratios to see how long it will take her to complete her homework
3 problems 20 problems
----------------- = --------------
4 minutes x minutes
Using cross products
3x = 4*20
3x= 80
Divide by 3
x = 80/3
x =26 2/3 minutes
She has 30 minutes
30 -26 2/3 = 3 1/3 minutes
3 minutes 20 seconds