Machine B takes 5 minutes to cut 50 pieces of lumbers. Machine C takes 11 minutes to cut 99 pieces of lumbers. Machine D takes 13 minutes to cut 156 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:
5 min → 50 pieces
1 min → 50 ÷ 5 = 10 pieces
Time taken by Machine C alone:
11 min → 99 pieces
1 min → 99 ÷ 11 = 9 pieces
Time taken by Machine D alone:
13 min → 99 pieces
1 min → 156 ÷ 13 = 12 pieces
Time taken by Machine B and Machine C together:
1 min → 10 + 9 = 19 pieces
Time taken by Machine C and Machine D together:
1 min → 9 + 12 = 21 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
= 21 - 19
= 2
Answer(s): (a) C, D or D, C; (b) 2