When a number is divided by 45, the remainder is 21. What will be the remainder when the number is divided by 15?

If $\rm tan A = {3 \over 8},$ then the value of ${3 \sin A + 2 \cos A} \over 3 \sin A - 2 \cos A$ is:

Rajdhani Express train of length 108 m is running at the speed of 128 km/h. Another train of length 148 m is standing at the station. In what time will the Rajdhani Express cross the other train?

The value of ${2 \over 3} - {5 \over 6} \times {4 \over 5} \div {4 \over 3} + {1 \over 2}$ is: