7. Determine the best buy (cheaper deal) in each of the following, a. 3 kg of washing powder for \( \$ 15.60 \) or 4 kg for \( \$ 19.80 \) b. 2 kg of Pink Lady apples for \( \$ 5.20 \) or 3 kg of Granny Smith apples for \( \$ 840 \) c. 3.2 litres of apple juice for \( \$ 5.60 \) or 4 litres of apple juice for \( \$ 680 \) d. 0.8 GB of internet usage for \( \$ 16 \) or 1.2 GB for \( \$ 25.80 \) with different service providers

To determine the best buy for each option, we will calculate the price per kilogram or per litre for each product and then compare them. ### a. Washing Powder 1. **3 kg for \$15.60**: \[ \text{Price per kg} = \frac{15.60}{3} = 5.20 \] 2. **4 kg for \$19.80**: \[ \text{Price per kg} = \frac{19.80}{4} = 4.95 \] **Conclusion**: The cheaper deal is **4 kg for \$19.80** at \$4.95 per kg. ### b. Apples 1. **2 kg of Pink Lady apples for \$5.20**: \[ \text{Price per kg} = \frac{5.20}{2} = 2.60 \] 2. **3 kg of Granny Smith apples for \$840**: \[ \text{Price per kg} = \frac{840}{3} = 280 \] **Conclusion**: The cheaper deal is **2 kg of Pink Lady apples for \$5.20** at \$2.60 per kg. ### c. Apple Juice 1. **3.2 litres for \$5.60**: \[ \text{Price per litre} = \frac{5.60}{3.2} = 1.75 \] 2. **4 litres for \$680**: \[ \text{Price per litre} = \frac{680}{4} = 170 \] **Conclusion**: The cheaper deal is **4 litres for \$680** at \$170 per litre. ### d. Internet Usage 1. **0.8 GB for \$16**: \[ \text{Price per GB} = \frac{16}{0.8} = 20 \] 2. **1.2 GB for \$25.80**: \[ \text{Price per GB} = \frac{25.80}{1.2} = 21.5 \] **Conclusion**: The cheaper deal is **0.8 GB for \$16** at \$20 per GB. ### Summary of Best Buys: - a. 4 kg of washing powder for \$19.80 - b. 2 kg of Pink Lady apples for \$5.20 - c. 4 litres of apple juice for \$680 - d. 0.8 GB of internet usage for \$16