Machine N takes 9 minutes to cut 108 pieces of lumbers. Machine P takes 10 minutes to cut 60 pieces of lumbers. Machine Q takes 11 minutes to cut 165 pieces of lumber. 

1. Which is the faster combination, N and P or P and Q? (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 N alone:
9 min → 108 pieces
1 min → 108 ÷ 9 = 12 pieces

Time taken by Machine P alone:
10 min → 60 pieces
1 min → 60 ÷ 10 = 6 pieces

Time taken by Machine Q alone:
11 min → 60 pieces
1 min → 165 ÷ 11 = 15 pieces

Time taken by Machine N and Machine P together:
1 min → 12 + 6 = 18 pieces

Time taken by Machine P and Machine Q together:
1 min → 6 + 15 = 21 pieces

Machine P and Q are the faster combination.

(b)
Number of more pieces of lumbers that can be cut by the faster combination (Machine P and Q) in 1 minute
= 21 - 18
= 3 

Answer(s): (a) P, Q or Q, P; (b) 3