Question 1029152

A biker decided to cover the distance of 120 km at a certain speed. However, he actually went 6 km/h slower so he arrived at his destination 1 hour later than he wanted to. What was the actual speed of the biker?
PS:If x is the actual speed of the biker, then what is the equation?
<pre>Since actual speed was x, then planned speed was: x + 6
Time taken to cover distance at actual speed: {{{120/x}}}
Time it would’ve taken to cover distance at planned speed: {{{120/(x + 6)}}}
The following TIME equation is thus formed: {{{120/x = 120/(x + 6) + 1}}}
120(x + 6) = 120x + x(x + 6) -------- Multiplying by LCD, x(x + 6) 
{{{120x + 720 = 120x + x^2 + 6x}}}
{{{x^2 + 120x + 6x - 120x - 720 = 0}}}
{{{x^2 + 6x - 720 = 0}}}
(x - 24)(x + 30) = 0
x, or ACTUAL speed was: {{{highlight_green(matrix(1,2, 24, "km/h"))}}}         OR        x = - 30 (ignore)