A bus travels at a speed of 60 km/h from town A to B. It returns to town A at a speed of 90 km/h using the same route. The whole journey takes 5 hours. Find the distance between A and B.

Let the distance between town A and town B be x km.

Time taken to travel from A to B = x/60 hours
Time taken to travel from B to A = x/90 hours

Total time taken = x/60 + x/90 = 5 hours

Multiplying through by 540 (LCM of 60 and 90) to clear the fractions, we get:
9x + 6x = 2700
15x = 2700
x = 180

Therefore, the distance between town A and town B is 180 km.

Let the distance between A and B be x km.

Time taken to travel from A to B:

```
Time = Distance / Speed
Time from A to B = x / 60 km/h
```

Time taken to travel from B to A:

```
Time from B to A = x / 90 km/h
```

Total time taken for the whole journey:

```
Total time = Time from A to B + Time from B to A
Total time = x / 60 + x / 90 = 5 hours
```

Solving for x:

```
x / 60 + x / 90 = 5
3x + 2x = 270
5x = 270
x = 270 / 5
x = 54 km
```

Therefore, the distance between town A and B is 54 km.