Example 1: use of the addition rule for disjoint events
a set of 40 cards consists of the following:
 10 black cards showing squares
 10 black cards showing circles
 10 red cards showing x’s
 10 red cards showing diamonds
a card will be selected at random from the set. find the probability that the card is black or shows a diamond.

The probability that the card is black or shows a diamond is 0.75

Step-by-step explanation:

The probability that the card is black or shows a diamond requires calculating the probabilities separately and adding them.

This is an example of Addition Rule for Disjoint Events

the sum of all the angles in a triangle are equal to 180

so you can add   the 3 given angles together to equal 180:

5y + 2y + 2y = 180

or since all three angles have the same letter, combine the 3 angles to equal 180:

9y = 180

complete the steps to find the area of the trapezoid.

area of rectangle = 256   square units

area of triangle 1 = 24  square units

area of triangle 2 = 16  square units

area of triangle 3 =   96 square units

area of trapezoid = 120  square units

step-by-step explanation: