Machine L takes 5 minutes to cut 65 pieces of lumbers. Machine M takes 10 minutes to cut 120 pieces of lumbers. Machine N takes 9 minutes to cut 99 pieces of lumber. 

1. Which is the faster combination, L and M or M and N? (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 L alone:
5 min → 65 pieces
1 min → 65 ÷ 5 = 13 pieces

Time taken by Machine M alone:
10 min → 120 pieces
1 min → 120 ÷ 10 = 12 pieces

Time taken by Machine N alone:
9 min → 120 pieces
1 min → 99 ÷ 9 = 11 pieces

Time taken by Machine L and Machine M together:
1 min → 13 + 12 = 25 pieces

Time taken by Machine M and Machine N together:
1 min → 12 + 11 = 23 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
= 25 - 23
= 2 

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