City E and City F are 357 km apart. At 5.20 p.m., Sam is travelling at a uniform speed left City E for City F while Albert set off from City F to City E along the same road at a uniform speed, which was 5 km/h slower than that of Sam. The two met at 8.20 p.m.
- Find the speed of Sam.
- If Albert 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 Sam and Albert to travel from 5.20 p.m. to 8.20 p.m. = 3 h
Average speed of Sam and Albert
= 357 ÷ 3
= 119 km/h
Sam's speed
= (119 + 5) ÷ 2
= 124 ÷ 2
= 62 km/h
(b)
Albert's speed
= 62 - 5
= 57 km/h
Distance that Albert travelled in 3 h
= 3 x 57
= 171 km
Remaining distance that Albert needed to travel
= 357 - 171
= 186 km
Time that Albert needed to reach his destination after the two met
= 186 ÷ 57
= 3
1557 = 3
519 h
Answer(s): (a) 62 km/h; (b) 3
519 h