Answer:
she can complete 20 math problems in 26 mins and 40 secs . she has 3 mins and 20 secs to talk to her friends
Step-by-step explanation:
She can solve 3 math problems in 4 mins
She can solve 1 math problem in = 4/3 *60 minutes= 80 secs
She has to solve 20 math problems = 20*80= 1600 secs/60= 26 mins and 40 secs.
She has 3 minutes and 20 secs to talk to her friends.