Dakota earned $15.75 in interest in account A and $28.0p in interest in account B after 21 months. If the simple interest rate is for 3.0% for account A and 4.0% for account B, which account had the greater principal? Explain.

Answer: account B had the greater capital.

Step-by-step explanation:

The formula for determining simple interest is expressed as

I = PRT/100

Where

I represents interest paid on the amount deposited.

P represents the principal or amount deposited

R represents interest rate

T represents the duration in years.

Considering account A,

I = $15.75

T = 21 months = 21/12 = 1.75 years

R = 3%

Therefore,

15.75 = (P * 3 * 1.75) / 100

15.75 = 0.0525P

P = 15.75/0.0525

P = 300

Considering account B,

I = $28

T = 21 months = 21/12 = 1.75 years

R = 4%

Therefore,

28 = (P * 4 * 1.75) / 100

28 = 0.07P

P = 28/0.07

P = $400

Therefore, account B had the greater capital.