Question

How many tiles are on the 4th layer?

Answer 1

80

Explanation:

if you take 10 + 100% of that then its 20 and 100% of that is 20 so now its 40 + 100% now its 80

1 layer 10

2 layer 20

3 layer 40

4 layer 80

Answer 2

100% of 10 is 10 meaning each layer increases 19 more than previous value.

1st layer=10

2nd layer= 20

3rd layer= 30

4th layer= 40

The forth layer contain 40 tiles