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Calculate simple interest and the cost of borrowing · Grade 9 · F1.3

Name: ______________________

Date: ______________________

1
Priya invests $1200 at a simple interest rate of 6% per year for 1 years. How much interest does she earn?
Warm-up
Answer:
2
Priya invests $1800 at a simple interest rate of 10% per year for 1 years. How much interest does she earn?
Warm-up
Answer:
3
Priya invests $400 at a simple interest rate of 9% per year for 5 years. How much interest does she earn?
Warm-up
Answer:
4
Priya invests $1900 at a simple interest rate of 7% per year for 2 years. How much will she have in total?
On level
Answer:
5
Priya invests $1200 at a simple interest rate of 9% per year for 1 years. How much will she have in total?
On level
Answer:
6
Priya invests $1200 at a simple interest rate of 9% per year for 5 years. How much will she have in total?
On level
Answer:
7
A car loan of $2500 is charged simple interest at 9% per year and repaid after 1 years. What is the total amount to repay?
Challenge
Answer:
8
A car loan of $8500 is charged simple interest at 12% per year and repaid after 2 years. What is the total amount to repay?
Challenge
Answer:
9
A car loan of $2500 is charged simple interest at 11% per year and repaid after 3 years. What is the total amount to repay?
Challenge
Answer:

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Worksheet code: eyJzIjoiZmluYW5jaWFsLXNpbXBsZS1pbnRlcmVzdCIsImQiOlsxODM3NDkzOTI2LDE3MjM2NTY2MjUsMTE1NzQ3NzI3OCw3NjEwNjI0MjksMTIzMjExNTUyMSwxMjc5NDI2MTI4LDExODM2NjQ1MTgsMjA2MzQ0NTcyNywxNzM0MzYxNzgxXSwidiI6MX0.b124462d8bde

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Answer key · Calculate simple interest and the cost of borrowing

1.
72 — I = P × r × t = $1200 × 6% × 1 = $72.
2.
180 — I = P × r × t = $1800 × 10% × 1 = $180.
3.
180 — I = P × r × t = $400 × 9% × 5 = $180.
4.
2166 — Interest = $266; total = $1900 + $266 = $2166.
5.
1308 — Interest = $108; total = $1200 + $108 = $1308.
6.
1740 — Interest = $540; total = $1200 + $540 = $1740.
7.
2725 — Interest = $2500 × 9% × 1 = $225; total to repay = $2500 + $225 = $2725.
8.
10540 — Interest = $8500 × 12% × 2 = $2040; total to repay = $8500 + $2040 = $10540.
9.
3325 — Interest = $2500 × 11% × 3 = $825; total to repay = $2500 + $825 = $3325.