The School Garden Budget
A Year 5 class has raised $240 for a garden project. They plan to buy 6 identical planter boxes at $18 each, 4 bags of soil at $9.50 per bag, and seedlings. After these purchases, they want to keep at least $40 for a watering can. The shop offers a 10% discount on the total cost of planter boxes and soil combined (not on seedlings), applied before adding seedling costs. A parent donates 2 extra bags of soil, so the class only needs to buy 2 bags. The students must decide the maximum amount they can spend on seedlings while still keeping $40 aside.
1. Calculate the maximum amount the class can spend on seedlings. Show each step.
Read the worked answer
Planter boxes: 6 × $18 = $108. Soil needed: 4 − 2 donated = 2 bags. Cost: 2 × $9.50 = $19. Combined boxes and soil: $108 + $19 = $127. Discount: 10% of $127 = $12.70, so discounted total = $127 − $12.70 = $114.30. Money available after discount and reserve: $240 − $114.30 − $40 = $85.70. So the maximum seedling spend is $85.70. A common trap is applying the discount to the full $240 or forgetting the donated soil reduces the bag count to 2, not 4.
2. The class actually finds seedlings priced at $12 per tray and wants to buy as many full trays as possible. How many trays can they buy, and how much money remains unspent after keeping the $40 reserve?
Read the worked answer
Each tray costs $12. Maximum trays = floor($85.70 ÷ $12) = floor(7.14) = 7 trays. Cost of 7 trays = 7 × $12 = $84. Total spent = $114.30 + $84 = $198.30. Remaining from $240 = $240 − $198.30 = $41.70. After setting aside the $40 reserve, unspent money = $41.70 − $40 = $1.70. Buying an 8th tray would cost $96, exceeding the $85.70 limit by $10.30, so 7 is correct.