City T and City U are 429 km apart. At 4.15 p.m., Bobby is travelling at a uniform speed left City T for City U while George set off from City U to City T along the same road at a uniform speed, which was 11 km/h slower than that of Bobby. The two met at 7.15 p.m.
- Find the speed of Bobby.
- If George 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 Bobby and George to travel from 4.15 p.m. to 7.15 p.m. = 3 h
Average speed of Bobby and George
= 429 ÷ 3
= 143 km/h
Bobby's speed
= (143 + 11) ÷ 2
= 154 ÷ 2
= 77 km/h
(b)
George's speed
= 77 - 11
= 66 km/h
Distance that George travelled in 3 h
= 3 x 66
= 198 km
Remaining distance that George needed to travel
= 429 - 198
= 231 km
Time that George needed to reach his destination after the two met
= 231 ÷ 66
= 3
3366 = 3
12 h
Answer(s): (a) 77 km/h; (b) 3
12 h