SOLUTION: Need help for the following sum: A starts walking north from Point X at 7 a.m. with a speed of 5 km/hr. After 1 hr, B starts from the same point cycling towards the east with a

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Question 486393: Need help for the following sum:
A starts walking north from Point X at 7 a.m. with a speed of 5 km/hr. After 1 hr, B starts from the same point cycling towards the east with a speed of 16 km/hr. At what time will they be at a distance of 52 km from each other?
Thanks
Answer by mananth(12270) About Me  (Show Source):
You can put this solution on YOUR website!
A ---- North ---- 5 km/h
B----- east ------16km/h (After 1 hour)
let the time be t
A distance 5t+5
B distance 16 t
(5t+5)^2+(16t)^2=52^2 ( I have used x in place of t)
25t^2+50t+25+256t^2=52^2
281t^2+50t-2679 =0
Find the roots of the equation by quadratic formula

a= 281 b= 50 c= -2679

b^2-4ac= 2500 - 3011196
b^2-4ac= 3013696 sqrt%28%093013696%09%29= 1736
x=%28-b%2B-sqrt%28b%5E2-4ac%29%29%2F%282a%29
x1=%28-b%2Bsqrt%28b%5E2-4ac%29%29%2F%282a%29
x1=( -50 + 1736 )/ 562
x1= 3 3
x2=( -50 -1736 ) / 562
x2= -3.18 -3 1/6
Ignore negative value
x = 3 hours
m.ananth@hotmail.ca