Usain Bolt runs a 100 m race and defeats his rival by 1 m. If Usain’s speed was 9 m/s, the speed of the rival was :
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → \( \displaystyle\frac{891}{100} \) m/s
“Defeats by 1 m” means that when Usain finishes 100 m, the rival has covered only 99 m in the same time.
\( \displaystyle \text{Usain's time}=\frac{100}{9}\ \text{s} \)
\( \displaystyle \text{Rival's speed}=\frac{99}{100/9} \)
\( \displaystyle =\frac{99\times 9}{100} \)
\( \displaystyle =\frac{891}{100}\ \text{m/s} \)