T*V=ST⋅V=S
V=velocity
T=time
S=route
S_p=70Sp=70
S_b=75Sb=75
V_p=V_b-5Vp=Vb−5
T_p=T_b+1.5Tp=Tb+1.5
T_p*V_p=S_pTp⋅Vp=Sp
T_b*V_b=S_bTb⋅Vb=Sb
=>⇒
(T_b+1.5)*(V_b-5)=70(Tb+1.5)⋅(Vb−5)=70
T_b*V_b=75Tb⋅Vb=75
I want to find V_bVb and V_pVp:
=>⇒
(T_b+1.5)*(V_b-5)=70(Tb+1.5)⋅(Vb−5)=70
T_b=75/V_bTb=75Vb
=>⇒
(75/V_b+1.5)*(V_b-5)=70(75Vb+1.5)⋅(Vb−5)=70
Let V_b=xVb=x
=> (75/x+1.5)*(x-5)=70⇒(75x+1.5)⋅(x−5)=70
=> 75-375/x+1.5x-7.5=70⇒75−375x+1.5x−7.5=70
=> -375/x+1.5x-2.5=0⇒−375x+1.5x−2.5=0
=> -375+1.5x^2-2.5x=0⇒−375+1.5x2−2.5x=0
=> 1.5x^2-2.5x-375=0⇒1.5x2−2.5x−375=0
=>⇒
x_(1,2)=(2.5+-sqrt((-2.5)^2-4*(1.5)*(-375)))/(2*1.5)x1,2=2.5±√(−2.5)2−4⋅(1.5)⋅(−375)2⋅1.5
=...=
x_1=50/3=16 2/3
x_2=-15
Velocity cannot be negative, so:
=>
x=16 2/3=V_b
=>
V_p=V_b-5=16 2/3-5=11 2/3