A paper airplane is thrown from the top of a hill and travels horizontally at 9 feet per second. If the plane descends 1 foot for
every 3 feet travelled horizontally, how many feet has the plane
descended after 5 seconds of travel?
A) 3
B) 10
C) 15
D) 20

step-by-step explanation:

first, eliminate the parenthesis:

3

x

+

2

−

4

x

second, group like terms:

3

x

−

4

x

+

2

third, combine like terms:

(

3

−

4

)

x

+

2

→

−

1

x

+

2

→

−

x

+

2

no

step-by-step explanation:

one fourth of 9% = 2.25%

gavin is correct in saying : the equivalent quarterly interest rate would be

2.25%.