Question #6fc66

1 Answer
Aug 26, 2016

One cyclist traveling towards North-West and another towards South.So angle between them is theta=(45+90)^@=135^@

Let the starting point of journey of two cyclists be O. After t hr first cyclist reaches at A traveling @ 22km/hr and at the same time the second cyclist reaches at B traveling @ 14km/hr .

"So in "DeltaAOB

/_ AOB=theta=135^@

OA=22t" km"

OB=14t" km"

AB=80" km"

Applying triangle law

AB^2=OA^2+OB^2-2OA*OBcostheta

=>80^2=(22t)^2+(14t)^2-2*22t*14tcos135^@

=>t^2(484+196+616*cos45^@)=6400

=>t^2(484+196+616*1/sqrt2)=6400

=>1115.58t^2=6400

=>t^2=6400/1115.58

=>t=sqrt(6400/1115.58)~~2.39hr