Machine F takes 8 minutes to cut 88 pieces of lumbers. Machine G takes 15 minutes to cut 90 pieces of lumbers. Machine H takes 12 minutes to cut 168 pieces of lumber. 

1. Which is the faster combination, F and G or G and H? (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 F alone:
8 min → 88 pieces
1 min → 88 ÷ 8 = 11 pieces

Time taken by Machine G alone:
15 min → 90 pieces
1 min → 90 ÷ 15 = 6 pieces

Time taken by Machine H alone:
12 min → 90 pieces
1 min → 168 ÷ 12 = 14 pieces

Time taken by Machine F and Machine G together:
1 min → 11 + 6 = 17 pieces

Time taken by Machine G and Machine H together:
1 min → 6 + 14 = 20 pieces

Machine G and H are the faster combination.

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

Answer(s): (a) G, H or H, G; (b) 3