Machine J takes 9 minutes to cut 90 pieces of lumbers. Machine K takes 17 minutes to cut 119 pieces of lumbers. Machine L takes 11 minutes to cut 143 pieces of lumber. 

1. Which is the faster combination, J and K or K and L? (Eg A, B) 
2. 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 J alone:
9 min → 90 pieces
1 min → 90 ÷ 9 = 10 pieces

Time taken by Machine K alone:
17 min → 119 pieces
1 min → 119 ÷ 17 = 7 pieces

Time taken by Machine L alone:
11 min → 119 pieces
1 min → 143 ÷ 11 = 13 pieces

Time taken by Machine J and Machine K together:
1 min → 10 + 7 = 17 pieces

Time taken by Machine K and Machine L together:
1 min → 7 + 13 = 20 pieces

Machine K and L are the faster combination.

(b)
Number of more pieces of lumbers that can be cut by the faster combination (Machine K and L) in 1 minute
= 20 - 17
= 3 

Answer(s): (a) K, L or L, K; (b) 3