Machine R takes 7 minutes to cut 84 pieces of lumbers. Machine S takes 13 minutes to cut 156 pieces of lumbers. Machine T takes 10 minutes to cut 140 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 → 84 pieces
1 min → 84 ÷ 7 = 12 pieces
Time taken by Machine S alone:
13 min → 156 pieces
1 min → 156 ÷ 13 = 12 pieces
Time taken by Machine T alone:
10 min → 156 pieces
1 min → 140 ÷ 10 = 14 pieces
Time taken by Machine R and Machine S together:
1 min → 12 + 12 = 24 pieces
Time taken by Machine S and Machine T together:
1 min → 12 + 14 = 26 pieces
Machine S and T are the faster combination.
(b)
Number of more pieces of lumbers that can be cut by the faster combination (Machine S and T) in 1 minute
= 26 - 24
= 2
Answer(s): (a) S, T or T, S; (b) 2