Manuscript

[sk8ternite]

Working together, Michelle and John can type a manuscript in 60 hours. How long does it take Martha and Jeff, working together, to type the same manuscript?
(1) Michelle types 60 words per minute and Jon types 40 words per minute
(2) Martha types 30 words per minute and Jeff types 80 words per minute

[JJJooe]

to answer the question, we've got to know the ratio of the speed of Martha and Jeff to that of Michelle and John. so i choose C.

this ratio is (30+80)/(60+40)=11/10

then it takes Martha and Jeff, working together, to type the same manuscript for (10/11)*60h=600/11 hours

[fruti_yum]

to answer the question, we've got to know the ratio of the speed of Martha and Jeff to that of Michelle and John. so i choose C.

this ratio is (30+80)/(60+40)=11/10

then it takes Martha and Jeff, working together, to type the same manuscript for (10/11)*60h=600/11 hours

IMO B is sufficient.

We need the rates for Marth and Jeff.. which we are given in B to find the number of hours they require!

[pathaniaus]

I think it should be C.

Michelle and John took 60 hours to write a manuscript.
Michelle and John together worked at a 100 words/minute

Rate * Time = Work; 100 words/minute * 60(60min) = 360000.

360000 is the total amount of words.

NOW, at 30 words per min for martha and 80 words per min for jeff, together they work at 110 words per minute.

Rate * Time = Work

110 words/minute * Time = 360000 words
Time = 360000/110

Therefore C.

[riteshbindal]

I also think C. Without knowing the correspondent ratio or speed of both the groups, we can't get the solution.

[sk8ternite]

OA is C