Question

Anyone know how to do this one
One Printer can do a printing job in 7 hours. Another printer can do the same job in 11 hours. How long can they do the job working together.

Answer 1

this is almost like doing
rate * time = distance, except you replace distance with 1 job
rate * time = 1 job

rate is in jobs/hour . so printer 1 has a rate of 1 job/7 hours
printer 2 has a rate of 1 job/11 hours

now do rate1* T + rate2*T = 1
where T is the time in hours
solve for T

Answer 2

kk thax

Answer 3

can you finish?

Answer 4

i got it thax :)