Question

Population of fungi in a yard produces 10 mushrooms in year 1, 20 in year 2, and 40 in year 3. if his trend continues, by year 5 there will be __________ mushrooms.

Answer 1

There will be 110 mushrooms I think.
Year one: 10
Year two: 10 plus 10
Year three: 20 plus 20
Year four: 40 plus 30
Year five: 70 plus 40 which equals 110 mushrooms.

Answer 2

10 times 2 = 20(y2)
20 times 2 = 40(y3)
40 times 2 = 80(y4)
80 times 2 = 160 (y5) 
A:160 mushrooms