Question 883505
Bicycle speed =x
time taken for 60 km = 60/x

motorbike speed = x+15
time taken for 60 km = 60/(x+15)

{{{60/x - 60/(x+15)=2}}}


multiply by x(x+15)

60(x+15)-60x =2x(x+15)

60x+90-60x=2x^2+30x

2x^2+30x-90 =0

/2
x^2+15x-45=0

degree two so quadratic equation