Machine B takes 5 minutes to cut 55 pieces of lumbers. Machine C takes 15 minutes to cut 90 pieces of lumbers. Machine D takes 13 minutes to cut 169 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 → 55 pieces
1 min → 55 ÷ 5 = 11 pieces
Time taken by Machine C alone:
15 min → 90 pieces
1 min → 90 ÷ 15 = 6 pieces
Time taken by Machine D alone:
13 min → 90 pieces
1 min → 169 ÷ 13 = 13 pieces
Time taken by Machine B and Machine C together:
1 min → 11 + 6 = 17 pieces
Time taken by Machine C and Machine D together:
1 min → 6 + 13 = 19 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
= 19 - 17
= 2
Answer(s): (a) C, D or D, C; (b) 2