City N and City P are 356 km apart. At 2.20 p.m., Warren is travelling at a uniform speed left City N for City P while Jack set off from City P to City N along the same road at a uniform speed, which was 10 km/h slower than that of Warren. The two met at 4.20 p.m.
- Find the speed of Warren.
- If Jack 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 Warren and Jack to travel from 2.20 p.m. to 4.20 p.m. = 2 h
Average speed of Warren and Jack
= 356 ÷ 2
= 178 km/h
Warren's speed
= (178 + 10) ÷ 2
= 188 ÷ 2
= 94 km/h
(b)
Jack's speed
= 94 - 10
= 84 km/h
Distance that Jack travelled in 2 h
= 2 x 84
= 168 km
Remaining distance that Jack needed to travel
= 356 - 168
= 188 km
Time that Jack needed to reach his destination after the two met
= 188 ÷ 84
= 2
2084 = 2
521 h
Answer(s): (a) 94 km/h; (b) 2
521 h