SOLUTION: car A travels x km for every litre of petrol.while car B travels (x+5)km for every litre of petrol. if car A uses 4 litres of petrol more than car B in covering 400km, find the num
Question 616937: car A travels x km for every litre of petrol.while car B travels (x+5)km for every litre of petrol. if car A uses 4 litres of petrol more than car B in covering 400km, find the number of litres of petril used by car B for the journey. Answer by ankor@dixie-net.com(22740) (Show Source):
You can put this solution on YOUR website! car A travels x km for every litre of petrol.while car B travels (x+5)km for every litre of petrol.
if car A uses 4 litres of petrol more than car B in covering 400km, find the number of litres of petril used by car B for the journey.
:
Car A's consumption - Car B consumption = 4 liters - = 4
:
multiply by x(x+5) to clear the denominators, results:
400(x+5) - 400x = 4x(x+5)
400x + 2000 - 400x = 4x^2 + 20x
:
Combine like terms, A quadratic equation
4x^2 + 20x - 2000 = 0
;
simplify, divide by 4
x^2 + 5x - 500 = 0
:
Factors to
(x+25)(x-20) = 0
:
the positive solution
x = 20 km/liter for Car A
then
25 km/liter for Car B
therefore
Car B: = 16 liters for 400 km journey
:
:
Confirm this solution by finding the consumption of Car A
400/20 = 20 liters, 4 liters more
