Answer:
35 :
t = 6.25 years
(about 6 years 3 months)
Equation:
t = (1/r)(A/P - 1)
Calculation:
First, converting R percent to r a decimal
r = R/100 = 4%/100 = 0.04 per year,
then, solving our equation
t = (1/0.04)((2500/2000) - 1) = 6.25
t = 6.25 years
The time required to get a total amount, principal plus interest, of $2,500.00 from simple interest on a principal of $2,000.00 at an interest rate of 4% per year is 6.25 years (about 6 years 3 months).
36:
The two distances are the same (out and back), so set them equal.
That is done by having a (rate)(time) equal a (rate)(time).
One time is “x” and the other is “4.8-x.”
One rate is 460 and the other is 500.
460 x = 500 (4.8 -x)
460 x = 2400 - 500x
900 x = 2400
x = 2.5 hours for the slower plane.
4.8- x = 2.3 hours for the faster plane.
