Problema Solution
It takes Stan 45 minutes to wash dishes and it takes Bobbie 30 minutes to wash dishes. How long would it take to wash the dishes if Stan and Bobbie did them at the same time?
Answer provided by our tutors
it takes Stan 45 minutes to wash dishes thus his rate is: 1/45 of the dishes per min
it takes Bobbie 30 minutes to wash dishes thus his rate is: 1/30 of the dishes per min
let x = minutes that Stan and Bobbie need to wash the dishes together
the together rate of Stan and Bobbie is: 1/x of the dishes per min
1/45 + 1/30 = 1/x
by solving we find:
x = 18 min
click here to see the step by step solution of the equality:
Stan and Bobbie will need 18 minutes to wash the dishes together.