Machine R takes 9 minutes to cut 180 pieces of lumbers. Machine S takes 12 minutes to cut 72 pieces of lumbers. Machine T takes 10 minutes to cut 180 pieces of lumber.
- Which is the faster combination, R and S or S and T? (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 R alone:
9 min → 180 pieces
1 min → 180 ÷ 9 = 20 pieces
Time taken by Machine S alone:
12 min → 72 pieces
1 min → 72 ÷ 12 = 6 pieces
Time taken by Machine T alone:
10 min → 72 pieces
1 min → 180 ÷ 10 = 18 pieces
Time taken by Machine R and Machine S together:
1 min → 20 + 6 = 26 pieces
Time taken by Machine S and Machine T together:
1 min → 6 + 18 = 24 pieces
Machine R and S are the faster combination.
(b)
Number of more pieces of lumbers that can be cut by the faster combination (Machine R and S) in 1 minute
= 26 - 24
= 2
Answer(s): (a) R, S or S, R; (b) 2