Correct option is (D) \(7\,\frac{1}{2}\) hrs
\(\because\) Time taken to fill a \(50\,l\) of tank = 5 hours
\(\therefore\) Time taken to fill a \(75\,l\) of tank \(=\frac5{50}\times75\;hours\)
\(=\frac{75}{10}\;hours\) = 7.5 hours
= 7 hours + \(\frac12\) hours
= \(7\frac12\) hours
Correct option is (D) 400 km
Speed of the car \(=\frac{Speed}{Time}\)
\(=\frac{300\,km}{6\,hours}\) = 50 km/h
Distance travelled by the car in 8 hours = speed \(\times\) time
= 50 km/h \(\times\) 8 hours
= (50 \(\times\) 8) km = 400 km
Correct option is (A) \(112\frac12\,km/hrs\)
Distance covered by train in \(2\frac12\) hrs = speed \(\times\) time
= 90 \(\times\) \(2\frac12\) km = 90 \(\times\) \(\frac52\) km
= 45 \(\times\) 5 km = 225 km
\(\therefore\) Speed required to covered same distance (225 km) in 2 hours \(=\frac{Distance}{Time}\)
\(=\frac{225}2\,km/hrs\) \(=112\frac{1}2\,km/hrs\)
