Question 303499
Ron can make as many pizzas in 30 minutes as Jess can make in 40 minutes. How long iwll it take to amekt eh same number if they both work?

doing a certain number of pizzas is one job

1/2  hour Ron completes 1 job

so in 1 hour he does 2 jobs 

2/3 hour jess takes for one job

in 1 hour he does 3/2 jobs

they both put to gether do 3/2 +2 jobs in 1 hour

=7/2 jobs in 1 hour

for 1 job they take 2/7 hours

=2/7 *60 minutes