City Q and City R are 492 km apart. At 4.59 p.m., Billy is travelling at a uniform speed left City Q for City R while Jeremy set off from City R to City Q along the same road at a uniform speed, which was 9 km/h slower than that of Billy. The two met at 8.59 p.m.
- Find the speed of Billy.
- If Jeremy 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 Billy and Jeremy to travel from 4.59 p.m. to 8.59 p.m. = 4 h
Average speed of Billy and Jeremy
= 492 ÷ 4
= 123 km/h
Billy's speed
= (123 + 9) ÷ 2
= 132 ÷ 2
= 66 km/h
(b)
Jeremy's speed
= 66 - 9
= 57 km/h
Distance that Jeremy travelled in 4 h
= 4 x 57
= 228 km
Remaining distance that Jeremy needed to travel
= 492 - 228
= 264 km
Time that Jeremy needed to reach his destination after the two met
= 264 ÷ 57
= 4
3657 = 4
1219 h
Answer(s): (a) 66 km/h; (b) 4
1219 h