Question

It takes 12 hours for a 900 km journey, if 180 km is done by bus and the rest by plane. It takes 30 minutes more, if 300 km is done by bus and the rest by plane. The ratio of the speed of the bus to that of the plane is:

• A. 3 : 5
• B. 3 : 7
• C. 3 : 4
• D. 4 : 3
• E. 5 : 3

Answer 1

The correct option is C

3 : 4

$Letthespeedofthebusbex\frac{km}{hr}andthatoftheplanebey\frac{km}{hr}.Then,\frac{180}{x}+\frac{720}{y}=12\to \frac{1}{x}+\frac{4}{y}=\frac{1}{15}------\left(i\right)Also,\frac{300}{x}+\frac{600}{y}=\frac{25}{2}\to \frac{1}{x}+\frac{2}{y}=\frac{1}{24}----\left(ii\right)Solving\left(i\right)and\left(ii\right),weget\to x=60andy=80,\to Ratioofspeeds=60:80=3:4$