Answer:
Any number between them both
I would use the starting position, sea level as zero. Then I would convert all those minutes to hours so the answer is an integer and not a decimal.
60 min * (-10 ft / 212 min) = -2.83 ft/hr
round to integer = -3 ft/hr
For this problem, you need to substitute 4 in for your variable t. the original equation is S(t) and the one you need is S(4) -- in other words, evaluate this equation when t = 4.
S(4) = 9(4) - 4
S(4) = 36 - 4
S(4) = 32 is your answer.
Interest earned in a month
(1.5/100) * 6000
90
Number of months in 4 years
12*4
48
So the interest earned in 4 years
90*48
4320 dollars