Question

Frank can type a report in 7hr. James can type a report in 6hr. How long will it take if they are working together?

Answer 1

guess!

Answer 2

Trick question, longer, because sharing a keyboard will make things difficult.

Answer 3

\[\frac{6\times 7}{6+7}\]

Answer 4

42/13

Answer 5

one the the job in m hours, other does the job in n hours. together then can do the job in
\[\frac{m\times n}{m+n}\] hours

Answer 6

yup,
\[\frac{42}{13}\]

Answer 7

Do I just reduce that

Answer 8

it does not reduce because 13 is prime. you could write as a mixed number if you like

Answer 9

3&3/13

Answer 10

yup

Answer 11

Thanks!

Answer 12

yw
hope method is clear

Answer 13

I am starting to get it!

Answer 14

good. i could write an explanation of you like, but the procedure is simple

Answer 15

I have trouble setting up the problem!

Answer 16

An expericened accountant can prepare a certain complexity of a tax return in 11hr. Another can do it in 22hr. How long will it take with them working together?

Answer 17

\[\frac{11\times 22}{11+22}\]

Answer 18

242/33

Answer 19

now it is just a computation

Answer 20

so basically just mutiply on top and add on bottom?

Answer 21

yes

Answer 22

then divide 33by 242?

Answer 23

one has a rate of
\[\frac{1}{11}\] other has a rate of
\[\frac{1}{22}\] combined rate is
\[\frac{1}{11}+\frac{1}{22}=\frac{22+11}{22\times 11}\]

Answer 24

you want to solve rate times time = 1 (one job) so time is reciprocal of combined rate which is
\[\frac{22\times 11}{22+11}\]

Answer 25

this reduces a lot

Answer 26

get
\[\frac{22}{3}\]

Answer 27

yes I got that to

Answer 28

or
\[7\tfrac{1}{3}\] if you prefer

Answer 29

or in time , 7 hours and twenty minutes

Answer 30

Thank you so much I understand it now!