Question

For question 1, find the interest. For question 2, find the ending balance. For question 3, find the selling price or cost price, depending on the information.

1. $194 at 7% each year for 13 years.

2. $939 at 8% for 6 years

3. Selling price: $21; Gain: 5%

Answer 1

1.176.54
2.1378.62
3.19.95

Answer 2

1. $176.54

2. $1389.72

3. $19.95

Explanation:

1. The simple interest formula is A = P ( 1 + rt).

P is the initial principal balance, so 194, r is the rate at which it increases in decimal form, so 0.07, and t is the time in years, so 13. That makes the equation:

A = 194 (1 + 0.07 * 13)

A = 370.54

To find the interest, subtract the initial principal balance from the final amount (A).

370.54 - 194 = 176.54

2. Using the same formula, A=P(1+rt)

P = 939

r = 0.08

t = 6

Substitute the values into the equation:

A = 939 (1 + 0.08 * 6)

A = 1389.72

3. 5% of $21 is gained.

0.05*21=1.05

$1.05 is the profit, meaning $21 - $1.05 = cost price

21 - 1.05 = 19.95.

So, the cost price was $19.95.