Select the correct answerIf speed of person is increased by 20% he reaches 15 min early. What is the initial time by the person?Options90 min40 min50 min120 min

To solve this problem, we need to understand that speed and time have an inverse relationship. If speed increases by a certain percentage, time decreases by that same percentage.

1. Let's denote the initial speed as S and the initial time as T.

2. The problem states that the speed of the person is increased by 20%. This means the new speed is 1.2S.

3. Because speed and time are inversely proportional, the new time is T/1.2.

4. The problem also states that the new time is 15 minutes earlier than the initial time. This means T - T/1.2 = 15.

5. Solving this equation for T gives T = 90 minutes.

So, the initial time taken by the person is 90 minutes.

To solve this problem, we need to understand that speed and time have an inverse relationship. If speed increases by a certain percentage, time decreases by that same percentage.

1. Let's denote the initial speed as S and the initial time as T.

2. The person increases their speed by 20%, so their new speed is 1.2S.

3. This new speed allows them to arrive 15 minutes earlier, so their new time is T - 15.

4. Because speed and time are inversely proportional, we can set up the following equation: S/T = 1.2S / (T - 15).

5. Simplifying this equation gives us T = 1.2(T - 15).

6. Solving for T gives us T = 1.2T - 18.

7. Subtracting 1.2T from both sides gives us -0.2T = -18.

8. Finally, solving for T gives us T = 90 minutes.

So, the initial time taken by the person was 90 minutes.