City R and City S are 468 km apart. At 4.13 p.m., Tommy is travelling at a uniform speed left City R for City S while Bryan set off from City S to City R along the same road at a uniform speed, which was 9 km/h slower than that of Tommy. The two met at 8.13 p.m.
- Find the speed of Tommy.
- If Bryan 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 Tommy and Bryan to travel from 4.13 p.m. to 8.13 p.m. = 4 h
Average speed of Tommy and Bryan
= 468 ÷ 4
= 117 km/h
Tommy's speed
= (117 + 9) ÷ 2
= 126 ÷ 2
= 63 km/h
(b)
Bryan's speed
= 63 - 9
= 54 km/h
Distance that Bryan travelled in 4 h
= 4 x 54
= 216 km
Remaining distance that Bryan needed to travel
= 468 - 216
= 252 km
Time that Bryan needed to reach his destination after the two met
= 252 ÷ 54
= 4
3654 = 4
23 h
Answer(s): (a) 63 km/h; (b) 4
23 h