City H and City J are 405 km apart. At 1.35 p.m., Riordan is travelling at a uniform speed left City H for City J while Andy set off from City J to City H along the same road at a uniform speed, which was 5 km/h slower than that of Riordan. The two met at 4.35 p.m.
- Find the speed of Riordan.
- If Andy 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 Riordan and Andy to travel from 1.35 p.m. to 4.35 p.m. = 3 h
Average speed of Riordan and Andy
= 405 ÷ 3
= 135 km/h
Riordan's speed
= (135 + 5) ÷ 2
= 140 ÷ 2
= 70 km/h
(b)
Andy's speed
= 70 - 5
= 65 km/h
Distance that Andy travelled in 3 h
= 3 x 65
= 195 km
Remaining distance that Andy needed to travel
= 405 - 195
= 210 km
Time that Andy needed to reach his destination after the two met
= 210 ÷ 65
= 3
1565 = 3
313 h
Answer(s): (a) 70 km/h; (b) 3
313 h