City L and City M are 480 km apart. At 6.55 p.m., Valen is travelling at a uniform speed left City L for City M while Brandon set off from City M to City L along the same road at a uniform speed, which was 8 km/h slower than that of Valen. The two met at 10.55 p.m.
- Find the speed of Valen.
- If Brandon continued to travel at the same speed, how long would it take for him to reach his destination after the two met? Express your answer in mixed number.
(a)
Time taken for Valen and Brandon to travel from 6.55 p.m. to 10.55 p.m. = 4 h
Average speed of Valen and Brandon
= 480 ÷ 4
= 120 km/h
Valen's speed
= (120 + 8) ÷ 2
= 128 ÷ 2
= 64 km/h
(b)
Brandon's speed
= 64 - 8
= 56 km/h
Distance that Brandon travelled in 4 h
= 4 x 56
= 224 km
Remaining distance that Brandon needed to travel
= 480 - 224
= 256 km
Time that Brandon needed to reach his destination after the two met
= 256 ÷ 56
= 4
3256 = 4
47 h
Answer(s): (a) 64 km/h; (b) 4
47 h