Respuesta :

Onoriodefelix

Answer:

1/2% or 0.5%

Step-by-step explanation:

R = 100 x I /P x T

Given

Interest I = $18

Principal P = $400 and

Time T = 9 months

Rate R = ?

Therefore

R = 100 x 18 /400 x 9

Multiply through

= 1800/3600

= 1/2% or 0.5%

I = prt

Simple interest (I) is money paid or earned for the use of money.

Principal (P) is the amount of money borrowed or deposited.

r annual interest rate (in decimal form).

t time (in years)

Find the annual interest rate

I = 18

P= $400

t = 9 months = 9/12 = 0.75 years

I = prt

18 =400 times R times 0.75  Substitute

18 = 300r   Multiply

18/300 = 300r/300   Divide both sides by 300

r = 0.06

The annual interest rate is 6%

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