Question

it takes one 8 hours to reach city A from city B . if i increase my speed by 6 km/hr , it takes me 1 hour 20 minutes less . find the distance between the two cities

Answer 1

Okay, here you need to use this formula:
Distance= speed×time.

Now, it takes 8 hours to reach A from B. Let the speed be x kmph.
So the distance between A and B is
$Distance= Speed\times time \implies Distance =8 \times x$

Now according to second condition, the speed is increased by 6 kmph.
And also the time decreases by 1 hour 20 minutes. So the time required will be 6 hours 40 minutes.
Now, 20 minutes is 1/3rd of an hour. So 40 minutes are 2/3rd of an hour.
This means the time actually taken will be $6 \frac{2}{3}$ hours and the speed is (x+6) kmph.

Now again, use the formula given earlier to get the answer using one variable.
I have solved in the pic.