Question

# A car can finish a certain journey in 10 hours at the speed of 48 km/hr. By how much should its speed be increased so that it may take only 8 hours to cover the same distance ?

Solution

## Let x km/hr be the speed. Then  Time (in hours)108Speed (in km/hr)48x Last period, more speed ∴ By inverse variation 10:8=x:48⇒108=x48⇒8x=10×48⇒x=10×488=60 ∴ Speed requird = 60 km/hr. Already speed = 48 km/hr. ∴ Speed to be increase = 60-48=12 km/hr

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