Solving exponential growth and decay problems

A concert has been sold out for weeks, and as the date of the concert draws closer, the price of the ticket increases. the cost of a pair of tickets was $150 yesterday and is $162 today. assuming that the cost continues to increases at this rate:

a. what is the daily rate of increases? what is the multiplier?

b. what will be the cost one week from now, the day before the concert?

c. what was the cost two weeks ago?

1 day increase

find percent increase

162-150=12

12/150=0.08

each day is 0.08 percent increase or 1.08 times the previous day

a.

rate is 0.08 per day more, but 1.08 times the previous day

first day is 150 so

f (x) = 150 (1.08) ^ (x-1)

that way, on first da, the 1.08 cancels out and turns to 1

b.

1 week from now is x=7

f (7) = 150 (1.08) ^ (7-1)

f (7) = 150 (1.08) ^6

f (7) = 238.031

about 238.03

c.

2 weeks ago

-14=x

f (-14) = 150 (1.08) ^ (-14-1)

f (-14) = 150 (1.08) ^-15

f (-14) = 47.286, round

price was 47.29

a. multiplier is 1.08

b.$238.03

c. $47.29