Machine H takes 5 minutes to cut 100 pieces of lumbers. Machine J takes 14 minutes to cut 140 pieces of lumbers. Machine K takes 10 minutes to cut 150 pieces of lumber. 

1. Which is the faster combination, H and J or J and K? (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 H alone:
5 min → 100 pieces
1 min → 100 ÷ 5 = 20 pieces

Time taken by Machine J alone:
14 min → 140 pieces
1 min → 140 ÷ 14 = 10 pieces

Time taken by Machine K alone:
10 min → 140 pieces
1 min → 150 ÷ 10 = 15 pieces

Time taken by Machine H and Machine J together:
1 min → 20 + 10 = 30 pieces

Time taken by Machine J and Machine K together:
1 min → 10 + 15 = 25 pieces

Machine H and J are the faster combination.

(b)
Number of more pieces of lumbers that can be cut by the faster combination (Machine H and J) in 1 minute
= 30 - 25
= 5 

Answer(s): (a) H, J or J, H; (b) 5