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    Question

    A car covers a distance of 60 km at a consistent speed.

    If the car's speed is increased by 8 km/h, it would take 2 hours less to travel the same distance. What was the car's original speed?
    A 12 km/h Correct Answer Incorrect Answer
    B 16 km/h Correct Answer Incorrect Answer
    C 10 km/h Correct Answer Incorrect Answer
    D 15 km/h Correct Answer Incorrect Answer

    Solution

    Let the actual speed of the car be 'x' km/h ATQ: Or,  60/x - 60/(x + 8) = 2 Or, 2x2 + 16x = 480 Or, x2 + 8x - 240 = 0 Or, x2 + 20x - 12x - 240 = 0 Or, x(x + 20) - 12(x + 20) = 0 Or, (x + 20)(x - 12) = 0 So, x = - 20, and x = 12 As speed cannot be negative So, x = 12 Original speed of the car is 12 km/h 

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