City Q and City R are 435 km apart. At 5.12 p.m., Cole is travelling at a uniform speed left City Q for City R while Riordan set off from City R to City Q along the same road at a uniform speed, which was 5 km/h slower than that of Cole. The two met at 8.12 p.m.
- Find the speed of Cole.
- If Riordan 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 Cole and Riordan to travel from 5.12 p.m. to 8.12 p.m. = 3 h
Average speed of Cole and Riordan
= 435 ÷ 3
= 145 km/h
Cole's speed
= (145 + 5) ÷ 2
= 150 ÷ 2
= 75 km/h
(b)
Riordan's speed
= 75 - 5
= 70 km/h
Distance that Riordan travelled in 3 h
= 3 x 70
= 210 km
Remaining distance that Riordan needed to travel
= 435 - 210
= 225 km
Time that Riordan needed to reach his destination after the two met
= 225 ÷ 70
= 3
1570 = 3
314 h
Answer(s): (a) 75 km/h; (b) 3
314 h