Question 11 of 45intermediate🔧 ApplyNumerical3 marks

Workers in a coffee plantation take 18 days to pick coffee berries in 20% of the plantation. How many days will they take to complete the picking work for the entire plantation, assuming the rate of work stays the same? Why is this assumption necessary?

Correct Answer

Given: 20% of the plantation takes 18 days to pick.

Calculation: (100/20) × 18 = 5×185 \times 18 = 90 days

Answer: 90 days

Why this assumption is necessary: The assumption that the rate of work stays the same is necessary because if workers work at different speeds in different areas, or if fatigue affects their speed, the calculation would not be accurate.

Exercise: Figure it Out (Section 2) | Q: 9 | (Page Page 14)
For More Understanding

Explanation

The chapter demonstrates proportional reasoning. If 20% takes 18 days, then the full 100% takes 5 times longer. The assumption about constant work rate is important because real-world conditions might vary.

Solution Steps

  1. 20% of plantation takes 18 days

  2. 100% = 5×205 \times 20%

  3. Days needed = 5×185 \times 18 = 90 days

  4. The assumption of constant work rate ensures proportional reasoning is valid

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