Machine Q takes 10 minutes to cut 120 pieces of lumbers. Machine R takes 14 minutes to cut 126 pieces of lumbers. Machine S takes 15 minutes to cut 210 pieces of lumber.
- Which is the faster combination, Q and R or R and S? (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 Q alone:
10 min → 120 pieces
1 min → 120 ÷ 10 = 12 pieces
Time taken by Machine R alone:
14 min → 126 pieces
1 min → 126 ÷ 14 = 9 pieces
Time taken by Machine S alone:
15 min → 126 pieces
1 min → 210 ÷ 15 = 14 pieces
Time taken by Machine Q and Machine R together:
1 min → 12 + 9 = 21 pieces
Time taken by Machine R and Machine S together:
1 min → 9 + 14 = 23 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
= 23 - 21
= 2
Answer(s): (a) R, S or S, R; (b) 2