Question

Superman and Batman took part in a race. The race involved going from $A$ to $B$ {1 km straight line} and coming back to $A$ along the same line. Superman ran with a constant speed of $15$ m/s both ways. Batman on his way from $A$ to $B$ ran at a constant speed of $10$ m/s but on his way back cheated by using his car which moved at a speed of $20$ m/s. Who won the race?

• A. Batman
• B. Superman
• C. Race ended in a tie
• D. Data insufficient

Answer 1

The correct option is B Superman

We will calculate the time taken by Superman and Batman to complete the race. One who took less time won the race.
Superman:
$\text{Time taken from A to B}=\frac{\text{distance}}{speed}=\frac{1\times {10}^3}{15}\text{s}$
$\text{Time taken from B to A}=\frac{\text{distance}}{\text{speed}}=\frac{1\times {10}^3}{15}\text{s}$
$\text{Total time in a race}=\frac{1000}{15}+\frac{1000}{15}=\frac{400}{3}=133.33\text{s}$
Batman
$\text{Time taken from A to B}=\frac{1000}{10}\text{s}$
$\text{Time taken from B to A}=\frac{1000}{20}\text{s}$
$\text{Total time in race}=\frac{1000}{10}+\frac{1000}{20}\text{s}=150\text{s}$
Superman took less time $\Rightarrow$ Superman won the race.