Plant 160 trees in the ratio 3:5

Two classes together have to plant 160 trees, shared between class one and class two in the ratio 3:5. How many trees does each class plant?

Step-by-step

1. 3 + 5 = 8
   Total parts = sum of all ratio terms
2. 160 ÷ 8 = 20
   Value of one part
3. 20 × 3 = 60
   Share for ratio term 1
4. 20 × 5 = 100
   Share for ratio term 2

Why it works

Sharing in a ratio means splitting the total into 3 + 5 = 8 equal parts; one part is the total divided by 8, and each share is that part multiplied by its own number of parts.

Common mistakes

• Dividing 160 by 5 instead of by the 3 + 5 = 8 parts in total.
• Giving the 60-tree share to the class that should receive 5 parts.

Related

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