Machine P takes 6 minutes to cut 120 pieces of lumbers. Machine Q takes 13 minutes to cut 117 pieces of lumbers. Machine R takes 7 minutes to cut 77 pieces of lumber.
- Which is the faster combination, P and Q or Q and R? (Eg A, B)
- In 1 minute, how many more pieces of lumbers can be cut by the faster combination compared to the other combination?
(a)
Time taken by Machine P alone:
6 min → 120 pieces
1 min → 120 ÷ 6 = 20 pieces
Time taken by Machine Q alone:
13 min → 117 pieces
1 min → 117 ÷ 13 = 9 pieces
Time taken by Machine R alone:
7 min → 117 pieces
1 min → 77 ÷ 7 = 11 pieces
Time taken by Machine P and Machine Q together:
1 min → 20 + 9 = 29 pieces
Time taken by Machine Q and Machine R together:
1 min → 9 + 11 = 20 pieces
Machine P and Q are the faster combination.
(b)
Number of more pieces of lumbers that can be cut by the faster combination (Machine P and Q) in 1 minute
= 29 - 20
= 9
Answer(s): (a) P, Q or Q, P; (b) 9