City E and City F are 374 km apart. At 5.20 p.m., Oliver is travelling at a uniform speed left City E for City F while Ethan set off from City F to City E along the same road at a uniform speed, which was 11 km/h slower than that of Oliver. The two met at 7.20 p.m.
- Find the speed of Oliver.
- If Ethan 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 Oliver and Ethan to travel from 5.20 p.m. to 7.20 p.m. = 2 h
Average speed of Oliver and Ethan
= 374 ÷ 2
= 187 km/h
Oliver's speed
= (187 + 11) ÷ 2
= 198 ÷ 2
= 99 km/h
(b)
Ethan's speed
= 99 - 11
= 88 km/h
Distance that Ethan travelled in 2 h
= 2 x 88
= 176 km
Remaining distance that Ethan needed to travel
= 374 - 176
= 198 km
Time that Ethan needed to reach his destination after the two met
= 198 ÷ 88
= 2
2288 = 2
14 h
Answer(s): (a) 99 km/h; (b) 2
14 h