28 miles per hour is your answer 154 divided by 5.5, simple math hon :) good luck.
Answer:
first, u need to know the formula for compound interest, which is:

where A is the final amount
P- initial amount
r- percent compounded(interest)
and
n- number of years
so
we have

3.8/100 = 0.038
1+0.038 =1.038
1.038^4 = 1.160885573136
475 * 1.160885573136 = 551.4206472396
approximately $551.42
9, 2, -5... so is going down by 7 each time, meaning the "common difference" is -7.