Question 930832
a1 leaves Davao at  9:50am for Manila cruising at 480 kph
a2 leaves Davao at 10:05am for Manila cruising at 600 kph
let x be the time it takes a2 to travel to Manila
a1 has a head start of 15 minutes or .25 hour
we have the following two equations set equal to each other, we use rate * time = distance
480*(x + .25) = 600 * x
480x + 120 = 600x
120x = 120
x = 1
a2 arrives at 11:05am and takes 1 hour