A coach is travelling from Town J to Town K. At 80 km/h, it will arrive three hours later than the scheduled time. At 90 km/h, it will arrive at two hours later than the scheduled time. What is the distance between Town J and Town K?
| |
Faster speed |
Slower speed |
| Speed |
90 km/h |
80 km/h |
| Time |
1 u + 2 |
1 u + 3 |
| Distance |
90 (1 u + 2) =
90 u + 180 |
80 (1 u + 3) =
80 u + 240 |
Distance covered for the faster speed or the slower speed is the same.
90 u + 180 = 80 u + 240
90 u - 80 u = 240 - 180
10 u = 60
1 u = 60 ÷ 10 = 6
Distance between Town J and Town K
= 90 u + 180
= 90 x 6 + 180
= 540 + 180
= 720 km
Answer(s): 720 km
