City F and City G are 528 km apart. At 6.56 p.m., Billy is travelling at a uniform speed left City F for City G while Bobby set off from City G to City F along the same road at a uniform speed, which was 8 km/h slower than that of Billy. The two met at 9.56 p.m.
- Find the speed of Billy.
- If Bobby 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 Billy and Bobby to travel from 6.56 p.m. to 9.56 p.m. = 3 h
Average speed of Billy and Bobby
= 528 ÷ 3
= 176 km/h
Billy's speed
= (176 + 8) ÷ 2
= 184 ÷ 2
= 92 km/h
(b)
Bobby's speed
= 92 - 8
= 84 km/h
Distance that Bobby travelled in 3 h
= 3 x 84
= 252 km
Remaining distance that Bobby needed to travel
= 528 - 252
= 276 km
Time that Bobby needed to reach his destination after the two met
= 276 ÷ 84
= 3
2484 = 3
27 h
Answer(s): (a) 92 km/h; (b) 3
27 h