A student measured the length of a room and obtained the measurement of 3.99m. If...
MATHEMATICS
WAEC 1998
A student measured the length of a room and obtained the measurement of 3.99m. If the percentage error of is measurement was 5% and his own measurement was smaller than the length , what is the length of the room?
- A. 3.78m
- B. 3.80m
- C. 4.18m
- D. 4.20m
Correct Answer: D. 4.20m
Explanation
Let the actual length of the room = y m
\(\therefore \frac{y - 3.99}{y} \times 100% = 5%\)
\(100(y - 3.99) = 5y \implies 100y - 399 = 5y\)
\(100y - 5y = 399 \implies y = \frac{399}{95}\)
y = 4.2 m
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