CAT (QA) PYQs

Two persons are walking beside a railway track at respective speeds of $2$ and $4 \mathrm{~km}$ per hour in the same direction. A train came from behind them and crossed them in $90$ and $100$ seconds, respectively. The time, in seconds, taken by the train to cross a stationary object?

The distance from $B$ to $C$ is thrice that from $A$ to $B$. Two trains travel from $A$ to $C$ via $B$. The speed of train $2$ is double that of train $1$ while traveling from $A$ to $B$ and their speeds are interchanged while traveling from $B$ to $C$. The ratio of the time taken by train $1$ to that taken by train $2$ in travelling from $A$ to $C$ is

A straight road connects points $A$ and $B.$ Car $1$ travels from $A$ to $B$ and Car $2$ travels from $B$ to $A$, both leaving at the same time. After meeting each other, they take $45$ minutes and $20$ minutes, respectively, to complete their journeys. If Car $1$ travels at the speed of $60 km/hr$, then the speed of Car $2,$ in km/hr, is