Question

Can someone explain this please.

Answer 1

Cory has 15 die-cast cars in his collection. Each year his collection increases by 20%. Roger has 40 cars in his collection. Each year he collects 1 additional car.

Part C: After approximately how many years is the number of cars that Cory and Roger have the same? Justify your answer mathematically

Answer 2

cory: y = 15*1.2^x
roger: y = 40 + 1*x
solve
15*1.2^x = 40 + 1*x

Answer 3

So for part A, Roger's function is relatively easy to figure out

Answer 4

So since he is constantly adding one more and he already starts with 40, we know it will be y=x+40
Where 40 is the constant (he starts with this many)
x is the rate at which he adds cars (he adds one so its 1x, but thats the same as x)

Answer 5

Okay, thanks!

Answer 6

np