A car is travelling from Town D to Town E. At 60 km/h, it will arrive five hours later than the scheduled time. At 80 km/h, it will arrive at two hours later than the scheduled time. What is the distance between Town D and Town E?
| |
Faster speed |
Slower speed |
| Speed |
80 km/h |
60 km/h |
| Time |
1 u + 2 |
1 u + 5 |
| Distance |
80 (1 u + 2) =
80 u + 160 |
60 (1 u + 5) =
60 u + 300 |
Distance covered for the faster speed or the slower speed is the same.
80 u + 160 = 60 u + 300
80 u - 60 u = 300 - 160
20 u = 140
1 u = 140 ÷ 20 = 7
Distance between Town D and Town E
= 80 u + 160
= 80 x 7 + 160
= 560 + 160
= 720 km
Answer(s): 720 km
