Machine Z takes 8 minutes to cut 120 pieces of lumbers. Machine A takes 15 minutes to cut 90 pieces of lumbers. Machine B takes 7 minutes to cut 84 pieces of lumber.
- Which is the faster combination, Z and A or A and B? (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 Z alone:
8 min → 120 pieces
1 min → 120 ÷ 8 = 15 pieces
Time taken by Machine A alone:
15 min → 90 pieces
1 min → 90 ÷ 15 = 6 pieces
Time taken by Machine B alone:
7 min → 90 pieces
1 min → 84 ÷ 7 = 12 pieces
Time taken by Machine Z and Machine A together:
1 min → 15 + 6 = 21 pieces
Time taken by Machine A and Machine B together:
1 min → 6 + 12 = 18 pieces
Machine Z and A are the faster combination.
(b)
Number of more pieces of lumbers that can be cut by the faster combination (Machine Z and A) in 1 minute
= 21 - 18
= 3
Answer(s): (a) Z, A or A, Z; (b) 3
