The speeds of two cars A and B are in the ratio 25 : 24. If the difference in their speeds is 12 km/h, then find the speed of car A (in km/hr).

The correct answer is 300.

Step 1: Define the speeds using the given ratio

We are given that the ratio of the speed of car A to car B is 25 : 24.

Let the common ratio multiplier be $x$.

Therefore:

Speed of car A = $25x$ km/h

Speed of car B = $24x$ km/h

Step 2: Use the difference in speeds to find $x$

The problem states that the difference in their speeds is 12 km/h.

$25x-24x=12$

$x=12$

Step 3: Calculate the speed of car A

Now, substitute the value of $x$ into the expression for the speed of car A:

Speed of car A = $25\times 12$

Speed of car A = $300$ km/h

Thus, the speed of car A is 300 km/h.