How many diagonals can be drawn by joining the vertices of an octagon?

A solid cube of 3 cm side, painted on all its faces, is cut up into small cubes of 1 cm side. How many of the small cubes will have exactly two painted faces?

Twelve equal squares are placed to fit in a rectangle of diagonal 5 cm. There are three rows containing four squares each. No gaps are left between adjacent squares. What is the area of each square?

Consider the following sum: • +1• +2• +• 3 + • 1 = 21• In the above sum, • stands for

A train 200 metres long is moving at the rate of 40 kmph. In how many seconds will it cross a man standing near the railway line?

If X is between -3 and -1, and Y is between -1 and 1, then X ² - Y² is in between which of the following?

X and Y are natural numbers other than 1, and Y is greater than X. Which of the following represents the largest number?