<PRE><B>Question 729729</B>
Ahmad boat A
Bryan boat B

They meet at P

BPA is right angled

Let Bryan take time  t

Ahmad takes t-2

in time t Bryan  goes 10 t km

in time (t-2) Ahmad goes 30 (t-2) km

(10t)^2 +(30(t-2))^2=60^2

100t^2+900t^2-3600t+3600=3600

1000t^2_3600t=0
1000t^2=3600t
1000t=3600
t=3.6 hours


Check

10*3.6 = 36 km

30*1.6 = 48 km

36^2+48^2=3600

60^2=3600


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