Question 298972
let her speed be x

she traveled 450 miles

time taken by her = 450/x

if her speed was x-15 it would have taken 450 /x + 15

450/x - 450 / x+15 = 1

450(x+15)-450x  / x(x+15)=1

450x +6750-450x =x^2 +15x

x^2+15x-6750=0

x^2+90x-75x-6750=0

x(x+90)-75(x+90)=0

(x-75)(x+90)=0

x=75 a positive value which is her speed