Machine K takes 10 minutes to cut 120 pieces of lumbers. Machine L takes 12 minutes to cut 84 pieces of lumbers. Machine M takes 8 minutes to cut 112 pieces of lumber. 

1. Which is the faster combination, K and L or L and M? (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 K alone:
10 min → 120 pieces
1 min → 120 ÷ 10 = 12 pieces

Time taken by Machine L alone:
12 min → 84 pieces
1 min → 84 ÷ 12 = 7 pieces

Time taken by Machine M alone:
8 min → 84 pieces
1 min → 112 ÷ 8 = 14 pieces

Time taken by Machine K and Machine L together:
1 min → 12 + 7 = 19 pieces

Time taken by Machine L and Machine M together:
1 min → 7 + 14 = 21 pieces

Machine L and M are the faster combination.

(b)
Number of more pieces of lumbers that can be cut by the faster combination (Machine L and M) in 1 minute
= 21 - 19
= 2 

Answer(s): (a) L, M or M, L; (b) 2