Abdul travels thrice the distance Catherine travels, which is also twice the distance that Binoy travels. Catherine's speed is $1/3$ of Abdul's speed, which is also $1/2$ of Binoy's speed. If they start at the same time then who reaches first?
To determine who reaches first, we need to compare the time taken by each person. The time taken is calculated using the formula: $t = \frac{d}{v}$ where $t$ is time, $d$ is distance, and $v$ is speed.
Let the distances traveled be $d_A, d_C, d_B$ and speeds be $v_A, v_C, v_B$ for Abdul, Catherine, and Binoy, respectively.
Let's express all distances and speeds in terms of a common reference, say Binoy's distance ($d_B$) and Abdul's speed ($v_A$):
Now, calculate the time taken for each person using $t = d/v$:
Comparing the calculated times:
Since $\frac{1}{2} < 6$, the time $t_B$ is the smallest value among the three. The person who takes the least time reaches first.
Therefore, Binoy reaches first.
With a certain set of diameters, a tractor's front wheels make 2 revolutions (revs) for every 1 revolution of the rear wheels. The effect of changing wheel diameter(s) is shown in the following plot. 
In this context, which of the following statements is CORRECT?
A car covers 4 successive stretches of 3 km each at speed of 10 kmph, 20 kmph, 30 kmph and 60 kmph respectively. The average speed of the car for the entire journey is: