If a person walks at 28 km/hr instead of 20 km/hr , he would have walked 30 km more . What is the actual distance travelled by him?45 km50 km75 km30 km40 km

Let's solve this step by step:

1. First, let's denote the actual distance the person travelled as 'D' (in km), and the time it took as 'T' (in hours).

2. From the problem, we know that the person usually walks at a speed of 20 km/hr. So, we can express the time 'T' it took him to travel the actual distance 'D' as T = D/20.

3. The problem also tells us that if the person walked at a speed of 28 km/hr, he would have walked 30 km more. So, we can express this hypothetical distance as D + 30. The time it would take him to walk this distance at 28 km/hr would be (D + 30)/28.

4. Since the time it takes to walk the actual distance at 20 km/hr and the time it takes to walk the hypothetical distance at 28 km/hr are the same, we can set the two expressions for 'T' equal to each other and solve for 'D':

   D/20 = (D + 30)/28

5. Multiplying both sides by 20*28 to get rid of the denominators gives us:

   28D = 20D + 600

6. Subtracting 20D from both sides gives us:

   8D = 600

7. Finally, dividing both sides by 8 gives us the actual distance 'D':

   D = 600 / 8 = 75 km

So, the actual distance travelled by the person is 75 km.