Machine C takes 5 minutes to cut 55 pieces of lumbers. Machine D takes 20 minutes to cut 200 pieces of lumbers. Machine E takes 12 minutes to cut 180 pieces of lumber.
- Which is the faster combination, C and D or D and E? (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 C alone:
5 min → 55 pieces
1 min → 55 ÷ 5 = 11 pieces
Time taken by Machine D alone:
20 min → 200 pieces
1 min → 200 ÷ 20 = 10 pieces
Time taken by Machine E alone:
12 min → 200 pieces
1 min → 180 ÷ 12 = 15 pieces
Time taken by Machine C and Machine D together:
1 min → 11 + 10 = 21 pieces
Time taken by Machine D and Machine E together:
1 min → 10 + 15 = 25 pieces
Machine D and E are the faster combination.
(b)
Number of more pieces of lumbers that can be cut by the faster combination (Machine D and E) in 1 minute
= 25 - 21
= 4
Answer(s): (a) D, E or E, D; (b) 4