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 A: Write functions to represent Cory and Roger's collections throughout the years. (4 points)
Part B: How many cars does Cory have after 6 years? How many does Roger have after the same number of years? (2 points)
Part C: After approximately how many years is the number of cars that Cory and Roger have the same? Justify your answer mathematically. (4 points)

Question

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 A: Write functions to represent Cory and Roger's collections throughout the years. (4 points)
Part B: How many cars does Cory have after 6 years? How many does Roger have after the same number of years? (2 points)
Part C: After approximately how many years is the number of cars that Cory and Roger have the same? Justify your answer mathematically. (4 points)

hahawowoh · Answer

please help

misty1212 · Answer

HI!!

misty1212 · Answer

you are not getting an answer because there is no information with which to answer it

hahawowoh · Answer

there I fixed it

misty1212 · Answer

to increase a number by $20\%$ multiply it by $100\%+20\%=120\%=1.2$ so a good function for cory is $$15\times 1.2^t$$

hahawowoh · Answer

I have everything just part c

misty1212 · Answer

i guess you are supposed to solve $$t+40=15\times (1.2)^t$$

misty1212 · Answer

it says "approximately" so i would use this http://www.wolframalpha.com/input/?i=t%2B40%3D15%281.2%29%5Et

misty1212 · Answer

or since you were already asked how many each had in six years, and since those numbers are almost equal, say "six"