Question 387153
sue can clean the kitchen alone in 1/3 hr or 20 minutes
jerry can clean the kitchen alone twice as long as sue =40 minutes
working together they can clean the kitchen in x minutes

sue's rate + jerry rate = the rate both working together

1/20 +1/40 =1/x
2/40 +1/40 =1/x
3/40 =1/x
x =40/3 =13.33 minutes

ans: working together sue and jerry can clean he kitchen in 13.33 minues