In a 700 m race, A reaches the finishing point in 30 seconds & B reaches in 35 seconds. By how much distance A beats B?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 100 m
When A finishes (after 30 seconds), B has run for 30 seconds only.
\( \displaystyle \text{Speed of B}=\frac{700}{35}=20\ \text{m/s} \)
\( \text{Distance run by B in 30 s}=20\times 30=600\ \text{m} \)
\( \text{A beats B by}\ 700-600=100\ \text{m} \)
Shortcut: B is 5 seconds behind, and in 5 seconds B runs \( 5\times 20=100 \) m.