many trees must each person planty When a hole is dug for one tree, 3 kg of mulch and \( 4,5 \mathrm{~kg} \) of fertiliser must be placed in the hole before the tree is planted. Another \( 0,5 \mathrm{~kg} \) of mulch must be spread around the tree. a. How much fertiliser and how much mulch must be bought for 120 trees?

For 120 trees, you will need to calculate both the fertiliser and the mulch requirements. For fertiliser, each tree requires \( 4.5 \, \text{kg} \). So, for 120 trees: \( 120 \times 4.5 \, \text{kg} = 540 \, \text{kg} \) of fertiliser. For mulch, you need \( 3 \, \text{kg} \) for each hole and an additional \( 0.5 \, \text{kg} \) to spread around the tree. This totals to \( 3 + 0.5 = 3.5 \, \text{kg} \) per tree. Consequently, for 120 trees: \( 120 \times 3.5 \, \text{kg} = 420 \, \text{kg} \) of mulch. To sum up, you will need **540 kg of fertiliser** and **420 kg of mulch** for planting 120 trees.