Problema Solution
Janet, an experienced shipping clerk, can fill a certain order in 6 hours. Tom, a new clerk, needs 7 hours to do the same job. Working together, how long will it take them to fill the order?
Answer provided by our tutors
the rate of Janet is 1/6 orders per hour
the rate of the new clerk is 1/7 orders per hour
let x = the hours they need to fill the order together
the together rate is 1/x orders per hour
the rate of Janet + the rate of the new clerk = the together rate
1/6 + 1/7 = 1/x
by solving we find
x = 42/13
x = 3 hr 3*60/13 min
x = 3 hr 14 min
it will take them 3 hours and 14 min to fill the order together.