A car is travelling from Town C to Town D. At 60 km/h, it will arrive four hours later than the scheduled time. At 70 km/h, it will arrive at two hours later than the scheduled time. What is the distance between Town C and Town D?
| |
Faster speed |
Slower speed |
| Speed |
70 km/h |
60 km/h |
| Time |
1 u + 2 |
1 u + 4 |
| Distance |
70 (1 u + 2) =
70 u + 140 |
60 (1 u + 4) =
60 u + 240 |
Distance covered for the faster speed or the slower speed is the same.
70 u + 140 = 60 u + 240
70 u - 60 u = 240 - 140
10 u = 100
1 u = 100 ÷ 10 = 10
Distance between Town C and Town D
= 70 u + 140
= 70 x 10 + 140
= 700 + 140
= 840 km
Answer(s): 840 km
