3 machines R, S, and T, working together at their respective rates, can do a certain job in 4 hours.
S and T, working together at their respective rates, can do the same job in 5 hours. How many hours would it take R, working alone at its rate, to do the same job ?
A) 8
B) 10
C) 12
D) 15
E) 20
This is a straightforward question ... I would say a 500-550 level question ... I am just keen to find out the following for this:
- trap/trick answers in the answer choices ... what are they and how can you spot them ?
- guessing strategy ... if you had to guess on this question, how would you guess ? which answer choices would you cross out ?
- alternative approaches ?
S and T, working together at their respective rates, can do the same job in 5 hours. How many hours would it take R, working alone at its rate, to do the same job ?
A) 8
B) 10
C) 12
D) 15
E) 20
This is a straightforward question ... I would say a 500-550 level question ... I am just keen to find out the following for this:
- trap/trick answers in the answer choices ... what are they and how can you spot them ?
- guessing strategy ... if you had to guess on this question, how would you guess ? which answer choices would you cross out ?
- alternative approaches ?
