Machine S takes 11 minutes to cut 187 pieces of lumbers. Machine T takes 14 minutes to cut 126 pieces of lumbers. Machine U takes 8 minutes to cut 120 pieces of lumber. 

1. Which is the faster combination, S and T or T and U? (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 S alone:
11 min → 187 pieces
1 min → 187 ÷ 11 = 17 pieces

Time taken by Machine T alone:
14 min → 126 pieces
1 min → 126 ÷ 14 = 9 pieces

Time taken by Machine U alone:
8 min → 126 pieces
1 min → 120 ÷ 8 = 15 pieces

Time taken by Machine S and Machine T together:
1 min → 17 + 9 = 26 pieces

Time taken by Machine T and Machine U together:
1 min → 9 + 15 = 24 pieces

Machine S and T are the faster combination.

(b)
Number of more pieces of lumbers that can be cut by the faster combination (Machine S and T) in 1 minute
= 26 - 24
= 2 

Answer(s): (a) S, T or T, S; (b) 2