Answer:

Step-by-step explanation:
The amount formula in compound interest is:

where:
P = principal amount
r = annual interest
n = number of compounding periods
t = number of years
We already know that:
P = $2000

t = 7 (number of years from 6th to 13th bday)
n = 4 (quarterly in a year)
Then,

4/5 = 8/10 = 12/15 = 16/20 = 20/25
Hope it helps
Answer:
7.5 m 457.5

Step-by-step explanation:
First, visualize the original cone and the smaller cone as overlapping similar triangles. The scale factor of the original cone to the smaller cone is 50:40, so if the smaller cone has a radius of 6 m, then the radius of the original cone would be 7.5 m.
The volume of the frustum is the volume of the original cone minus the volume of the smaller cone. The formula for the volume of a cone is V =
.
Original Cone =
=
= 937.5
Smaller Cone =
=
= 480
Frustum = 937.5
- 480
= 457.5
Answer:
6 minutes
Step-by-step explanation:
'a' in the formula represents altitude in feet. You are told the altitude is 21000 feet, so put that into the formula:
21000 = 3400t +600
You can solve this for t:
20400 = 3400t . . . . . subtract 600 from both sides
6 = t . . . . . . . . . . . . . . . divide both sides by 3400
The problem statement tells you that t represents minutes after lift off, so this solution means the altitude is 21000 feet 6 minutes after lift off.
The question is asking for the number of minutes after lift off that the plane reaches an altitude of 21000 feet, so this answers the question directly:
The plane is at an altitude of 21000 feet 6 minutes after lift off.
Im not sure but I’ll go with c :)