If a worker can do his job in 5 hours, and a student can do the same job in 8 hours, what part of the work is left to finish after two hours of work? NOTE: THEY WORKED TOGETHER ANSWER: FRACTIOn

Part of work left to finish after two work hours is 7/20

Step-by-step explanation:

Firstly, we need to calculate their joint work rate

That will be;

1/(1/5 + 1/8) = 1/(13/40) = 40/13

This means that they will complete the task in 40/13 hours

1 whole part takes 40/13

x part will take 2 hours

x * 40/13 = 2

40x = 26

x = 26/40

So the part that will be completed in two hours is 26/40

This means that the part left to complete will be:

1 - 26/40 = 14/40 = 7/20

7/20

Step-by-step explanation:

you need to find what is left, not how much they did (which is 13/20)

answer: the correct one is a

step-by-step explanation: