After 4 years, $3,006 deposited in a savings account with simple interest had grown to a total of $3,967.92. What was the interest rate?

So interest rate is 8% per annum

Step-by-step explanation:

Principal amount = $3,006

Amount at end = $3,967.92

Time = 4yrs

interest money = ($3967.92 - $3006)  

also equal to = 4 * (x/100) * $3,006

Where x is the interest rate per annum

So, 4 * (x/100) * $3,006 = ($3967.92 - $3006)

        x = 8%

So interest rate is 8% per annum

36 girls

step-by-step explanation:

the 48 boys is 4 parts of the ratio

divide 48 by 4 to obtain one part of the ratio

= 12 ← 1 part of the ratio

3 parts = 3 × 12 = 36 ← number of girls