how do you solve this problem?
" two combines harvest a field in 10 hours, if one combine can complete the job in 30 hours, how long should it take the other combine to harvest the field alone? "

Question

how do you solve this problem? 
" two combines harvest a field in 10 hours, if one combine can complete the job in 30 hours, how long should it take the other combine to harvest the field alone? "

anonymous · Answer

1 C  completes 1 Field in 30 hrs
.... > in ! hr 1 C completes 1/30 Field
2 C complete 1 Field in 10 hrs
...> In 1 hr 2 C complete 1/10 Field

... > in 1 hr the second C completes ( 1/10  - 1/30) = 2/30
=1/15 Field
..> he completes 1 field in 15 hrs

anonymous · Answer

let us suppose their are two people A & B
A can complete the job in 30 hrs so in one hour he will complete (1/30) th job
simmilarly B can complete the job in one hour = (1/10) th job
therefore in a hour both will do = (1/30)+(1/10)
 there fore both together will complete the work in

(15/2) hrs = 7.5 hrs

anonymous · Answer

i was telling u the process to calculate

anonymous · Answer

they complete the field in 10 when together

anonymous · Answer

sagar i was telling the process used so i had assumed two different peersons A and B

anonymous · Answer

so is it 15 hours or 7.5? I'm confused. o:

anonymous · Answer

hey i was telling u the procedure in this case your answer is 15 hrs.
i was just explaining u the things how to calculate

anonymous · Answer

oh okay, thank you.