A district has 300 km of roads. The government increases the length by 15% in the first year and by 10% in the second year. How many km of roads will there be after the two years? Round to the nearest whole number.
Answer
380
The correct answer is 380 — Answer: 380.
Step-by-step solution
- Initial road length = 300 km.
- First year increase: 15% of 300 = 0.15×300 = 45 km; new length = 300 + 45 = 345 km.
- Second year increase: 10% of 345 = 0.10×345 = 34.5 km; new length = 345 + 34.5 = 379.5 km.
- Round 379.5 to nearest integer = 380 km.
- Answer: 380.
Common mistake: Adding percentages instead of compounding them
Concept tested: Percentage increase over successive years
Published · How this solution was prepared and checked
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