CAT 2020 Quant Question [Slot 2] with Solution 03

Let the length of the racetrack be D.

When A covers D km, B covers ( D -45) km and C covers (D-90) km

When B covers D km, C covers ( D -50) km

The ratio of the speeds of the racers is same as the ratio of the distance travelled in a given time period.

Ratio of speed of B and C is \(\frac{{{\text{ Speed of }}B}}{{{\text{ Speed of }}C}} = \frac{{D - 45}}{{D - 90}} = \frac{D}{{D - 50}}\)

\( \Rightarrow \frac{D}{{D - 50}} = \frac{{45}}{{40}}\)

\( \Rightarrow 40D = 45D - 50 \times 45\)

\( \Rightarrow D = 450\)