There are 7 black, 5 white and 4 orange balls in a bag. Four balls are drawn without replacement. Find the probability that at least 3 balls are white.
15 countries took part in The World Cup. Each team played exactly 2 matches. The winner scored 3 points and the loser scored 0 points. Each team got 1 point for a draw. How many more points at most did the champion score than the runner up?
In the figure below, ABCD is a rectangle, E and F are midpoints of AD and CE, respectively. If the area of $\triangle BDF$ is $7.5\text{ cm}^2$, find the area of ABCD in square centimetres.
The source figure is absent; the following is an authored reconstruction from the stated givens.
Two thirds of the journey from Lethbridge to Medicine Hat is highway; the remaining third is country road. St. Paul connects them. A van leaves Lethbridge for Medicine Hat at 100 km/h on highway and 60 km/h on country road. A car leaves Medicine Hat for Lethbridge at 70 km/h on country road and 110 km/h on highway. They pass 44 km from St. Paul. Find the distance between the two cities, in km.
The common chord AB of circles with centres m and n has length 2(3). It forms one side of an equilateral triangle in circle m and one side of a right hexagon in circle n. Find the ratio of their areas.
Starting from any letter M below, the word MADAM can be spelled by moving up, down, left or right to an adjacent letter. How many ways are there to spell MADAM?