Erica could do 10 math problems in 20 minutes. Penny could do 15 math problems in 25 minutes. If they worked
together, how many minutes would it take Erica and Penny to do 30 math problems?
it’ll take erica 60 minutes (an hour) to do 30 math problems and it’ll take penny 50 minutes to do 30. but together, it should take about 45-55 minutes to do 30
