SOLUTION: A motorist travels 60 km at x km/hr and 180 km at y km/hr and takes 10 hours altogether for the journey. If the speeds are interchanged, the journey takes 8hr 40mins. Find x and y

Question 1122925: A motorist travels 60 km at x km/hr and 180 km at y km/hr and takes 10 hours altogether for the journey. If the speeds are interchanged, the journey takes 8hr 40mins. Find x and y
Found 2 solutions by josgarithmetic, MathTherapy:
Answer by josgarithmetic(39620) (Show Source): You can put this solution on YOUR website!

Substitute the new variables.

Back-substitute:

------speed for second part of journey

-------speed for first part of journey
Answer by MathTherapy(10552) (Show Source): You can put this solution on YOUR website!

A motorist travels 60 km at x km/hr and 180 km at y km/hr and takes 10 hours altogether for the journey. If the speeds are interchanged, the journey takes 8hr 40mins. Find x and y

60y + 180x = 10xy ------ Multiplying by LCD, xy ------ eq (i)

540y + 180x = 26xy ----- Multiplying by LCD, 3xy ------- eq (ii)
480y = 16xy ------------ Subtracting eq (i) from eq (ii)

------ Substituting 30 for x in eq (i)

2y + 180 = 10y
180 = 10y - 2y
180 = 8y

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