It takes jo 90 seconds to cut a a certain type of wood into 10 pieces. how long would it take jo to cut the same wood type into 20 pieces?

So 90 seconds=10 pieces
10 pieces=9 cuts because just subtract 1 from number of pieces
2 pieces=1 cut
10 pieces=9 cust

90 seconds=9 cuts
10 seconds=1 cut

20-1=19
20 pieces=19 cuts
10 seconds per cut
10 times 19=190 seconds

it would take 190 seconds to cut into 20 pieces

In the space of 90 seconds Jo cuts a certain type of wood into 10 pieces.

Technically, this means that he had to strike that piece of wood 9 times.

So we can say that he strikes the piece of wood once every 10 seconds.



If he continues striking the wood at this pace, it will take him 190 seconds to make 20 separate pieces of wood, as he'd have to make 19 cuts.

Here is the sequence of strikes:

10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190



The answer is 190 seconds.