Machine Q takes 7 minutes to cut 77 pieces of lumbers. Machine R takes 17 minutes to cut 170 pieces of lumbers. Machine S takes 10 minutes to cut 130 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:
7 min → 77 pieces
1 min → 77 ÷ 7 = 11 pieces
Time taken by Machine R alone:
17 min → 170 pieces
1 min → 170 ÷ 17 = 10 pieces
Time taken by Machine S alone:
10 min → 170 pieces
1 min → 130 ÷ 10 = 13 pieces
Time taken by Machine Q and Machine R together:
1 min → 11 + 10 = 21 pieces
Time taken by Machine R and Machine S together:
1 min → 10 + 13 = 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