City Y and City Z are 414 km apart. At 3.40 p.m., Ryan is travelling at a uniform speed left City Y for City Z while Julian set off from City Z to City Y along the same road at a uniform speed, which was 12 km/h slower than that of Ryan. The two met at 6.40 p.m.
- Find the speed of Ryan.
- If Julian 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 Ryan and Julian to travel from 3.40 p.m. to 6.40 p.m. = 3 h
Average speed of Ryan and Julian
= 414 ÷ 3
= 138 km/h
Ryan's speed
= (138 + 12) ÷ 2
= 150 ÷ 2
= 75 km/h
(b)
Julian's speed
= 75 - 12
= 63 km/h
Distance that Julian travelled in 3 h
= 3 x 63
= 189 km
Remaining distance that Julian needed to travel
= 414 - 189
= 225 km
Time that Julian needed to reach his destination after the two met
= 225 ÷ 63
= 3
3663 = 3
47 h
Answer(s): (a) 75 km/h; (b) 3
47 h