Question 949225
A lorry and a car both travel a 240 mile journey at constant speeds. 

The car is travelling at 12mph faster than the lorry. 

The lorry takes one hour longer to complete the journey.

If 'x' is the speed of the car, show an algebraic equation to show 'x'.
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t = d/r
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Time for the car = 240/x hours
Time for the lorry = 240/(x-12)
(240/x) + 1 = 240/(x-12) 
(240 + x)/x = 240/(x-12)
(x+240)*(x-12) = 240x
{{{x^2 + 228x - 2880 = 240x}}}
{{{x^2 - 12x - 2880 = 0}}}
(x - 60)*(x + 48) = 0
x = 60
Ignore the x = -48