A type E machine can complete a job in 5 hours and a type B machine can complete the job in 7 hours. How many hours will it take 2 type E machines and 3 type B machines working together and independently to complete the job? Choose the most appropriate option:
A) 1/5
B) 29/35
C) 5/6
D) 35/29
E) 35/12
now D should be the answer.   E need 5 hours to complete   and B needs 7 hours to compete   so 2E + 3B will complete 2/5 + 3/7 or 29/35 portion of the job in 1 hour   so the whole job will take 35/29 hours....=35/29
<result>D</result>
A type E machine can complete a job in 5 hours and a type B machine can complete the job in 7 hours. How many hours will it take 2 type E machines and 3 type B machines working together and independently to complete the job?