City P and City Q is 616 km apart. Albert left City P for City Q at 7.00 a.m. travelling at an average speed of 77 km/h. Japheth left City P later than Albert and caught up with him at 11.00 a.m. Japheth was travelling at a speed of 112 km/h.

1. At what time did Japheth leave City P?
2. How much later did Albert arrive in City Q than Japheth? Express your answer in h as a fraction or mixed number.

(a)
From 7.00 a.m. to 11.00 a.m. = 4 h

Distance that Albert covered when Japheth caught up with Albert
= 4 x 77
= 308 km

Time that Japheth took to travel 308 km
= 308 ÷ 112
= 2³₄ h

1 h = 60 min
³₄ h = ³₄ x 60 = 45 min
2³₄ h = 2 h 45 min

Time that Japheth left City P:
2 h 45 min before 11.00 a.m. = 8.15 a.m.

(b)
Remaining distance that they had to cover to reach City Q
= 616 - 308
= 308 km

Duration that Japheth had to travel before reaching City Q
= 308 ÷ 112
= 2³₄ h

Duration that Albert had to travel before reaching City Q
= 308 ÷ 77
= 4 h

Duration that Albert took to arrive later than Japheth in City Q
= 4 - 2³₄
= 1¹₄ h

Answer(s): (a) 8.15 a.m.; (b) 1¹₄ h