Machine B takes 6 minutes to cut 66 pieces of lumbers. Machine C takes 20 minutes to cut 140 pieces of lumbers. Machine D takes 14 minutes to cut 210 pieces of lumber.
- Which is the faster combination, B and C or C and D? (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 B alone:
6 min → 66 pieces
1 min → 66 ÷ 6 = 11 pieces
Time taken by Machine C alone:
20 min → 140 pieces
1 min → 140 ÷ 20 = 7 pieces
Time taken by Machine D alone:
14 min → 140 pieces
1 min → 210 ÷ 14 = 15 pieces
Time taken by Machine B and Machine C together:
1 min → 11 + 7 = 18 pieces
Time taken by Machine C and Machine D together:
1 min → 7 + 15 = 22 pieces
Machine C and D are the faster combination.
(b)
Number of more pieces of lumbers that can be cut by the faster combination (Machine C and D) in 1 minute
= 22 - 18
= 4
Answer(s): (a) C, D or D, C; (b) 4