Gr 9 Revision questions 14 October 2025 (Chapters 1-13)

An investment of R2500 is made into an account which pays compound interest at 8% per annum. How much will the investment be worth after two years?

• R2,916

• R2,800

• R2,700

• R3,000

Answer explanation

To calculate the future value of the investment, use the formula A = P(1 + r/n)^(nt). Here, P = 2500, r = 0.08, n = 1, and t = 2. This gives A = 2500(1 + 0.08/1)^(1*2) = 2916. Thus, the investment will be worth R2,916.

Find the HCF of 40 and 56.

• 8

• 4

• 12

• 16

Answer explanation

To find the HCF of 40 and 56, we list the factors: 40 (1, 2, 4, 5, 8, 10, 20, 40) and 56 (1, 2, 4, 7, 8, 14, 28, 56). The common factors are 1, 2, 4, and 8. The highest is 8, making it the HCF.

Find the LCM of 40 and 56.

• 280

• 320

• 240

• 560

Answer explanation

To find the LCM of 40 and 56, we can use the prime factorization method. The prime factors of 40 are 2^3 and 5, and for 56, they are 2^3 and 7. The LCM is found by taking the highest power of each prime: 2^3, 5, and 7, which gives us 280.

25kg of sugar can be bought wholesale for R600. Find the cost of 1kg of sugar.

• R24

• R20

• R25

• R30

Answer explanation

To find the cost of 1kg of sugar, divide the total cost by the total weight: R600 ÷ 25kg = R24. Therefore, the cost of 1kg of sugar is R24.

25kg of sugar can be bought wholesale for R600. How many Kg of sugar can be bought for R1440?

• 60 kg

• 50 kg

• 75 kg

• 100 kg

Answer explanation

25 kg of sugar costs R600, so 1 kg costs R24. For R1440, you can buy R1440 / R24 = 60 kg of sugar. Thus, the correct answer is 60 kg.

R400 is being split between Noah, Nellie and Nolwazi in the ratio 10:8:7. How much will Nellie receive?

• R128

• R140

• R112

• R160

Answer explanation

The total parts in the ratio 10:8:7 is 25. Nellie's share is 8/25 of R400, which equals R128. Therefore, Nellie will receive R128.

Write 120 as the product of prime factors.

Answer explanation

To factor 120, we divide by the smallest prime, 2: 120 ÷ 2 = 60, 60 ÷ 2 = 30, 30 ÷ 2 = 15. Then, 15 ÷ 3 = 5. Thus, 120 = 2^3 × 3 × 5, confirming the correct choice is 2^3 × 3 × 5.

Write 216 as the product of prime factors.

Answer explanation

To factor 216, we divide by 2: 216 = 2 × 108, 108 = 2 × 54, 54 = 2 × 27. Then, 27 = 3 × 9, 9 = 3 × 3. Thus, 216 = 2^3 × 3^3, confirming the correct choice is 2^3 × 3^3.

Find the next two numbers in the sequence: 1000, 850, 700, 550, 400, 250, ___, ___

• 100, -50

• 150, 0

• 200, 50

• 50, -100

Answer explanation

The sequence decreases by 150 each time: 1000-150=850, 850-150=700, and so on. Continuing this pattern, 250-150=100 and 100-150=-50. Thus, the next two numbers are 100 and -50.

Find the next two numbers in the sequence: 81, 243, 729, 2187, ___, ___

• 6561, 19683

• 7290, 21870

• 59049, 177147

• 2430, 7290

Answer explanation

The sequence is a geometric progression where each number is multiplied by 3. Continuing this pattern, 2187 x 3 = 6561 and 6561 x 3 = 19683. Thus, the next two numbers are 6561 and 19683.