Machine R takes 7 minutes to cut 98 pieces of lumbers. Machine S takes 13 minutes to cut 156 pieces of lumbers. Machine T takes 12 minutes to cut 120 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:
7 min → 98 pieces
1 min → 98 ÷ 7 = 14 pieces
Time taken by Machine S alone:
13 min → 156 pieces
1 min → 156 ÷ 13 = 12 pieces
Time taken by Machine T alone:
12 min → 156 pieces
1 min → 120 ÷ 12 = 10 pieces
Time taken by Machine R and Machine S together:
1 min → 14 + 12 = 26 pieces
Time taken by Machine S and Machine T together:
1 min → 12 + 10 = 22 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 - 22
= 4
Answer(s): (a) R, S or S, R; (b) 4