概率与条件概率

Each rock in a collection of 70 rocks was classified as either igneous, metamorphic, or sedimentary, as shown in the frequency table.

If one of these rocks is selected at random, what is the probability of selecting a rock that is igneous?

The table shows the distribution of the 162 igneous rocks in a certain earth science laboratory by mineral composition and texture. What fraction of the laboratory's granitic rocks are coarse‑grained?

Each face of a fair 12-sided die is labeled with a number from 1 through 12, with a different number appearing on each face. If the die is rolled one time, what is the probability of rolling a 5?

Each face of a fair 20-sided die is labeled with a number from 1 through 20, with a different number appearing on each face. If the die is rolled one time, what is the probability of rolling a 9?

Each face of a fair 16-sided die is labeled with a number from 1 through 16, with a different number appearing on each face. If the die is rolled one time, what is the probability of rolling a 4?

For a particular machine that produces beads, 29 out of every 100 beads it produces have a defect. A bead produced by the machine will be selected at random. What is the probability of selecting a bead that has a defect?

A total of 50 children attended a summer camp and were offered 4 types of sandwiches. The table shows the number of children who chose each type of sandwich.

If one of these children is selected at random, what is the probability of selecting a child who chose a vegetarian sandwich?

Set K consists of all the positive integers that are less than or equal to 160, where none of the integers are repeated. If a number is selected at random from set K, what is the probability of selecting a number that is even and less than or equal to 50?

The table summarizes the distribution of color and shape for 100 tiles of equal area.

	Red	Blue	Yellow	Total
Square	10	20	25	55
Pentagon	20	10	15	45
Total	30	30	40	100

If one of these tiles is selected at random, what is the probability of selecting a red tile? (Express your answer as a decimal or fraction, not as a percent.)

Each face of a fair 14-sided die is labeled with a number from 1 through 14, with a different number appearing on each face. If the die is rolled one time, what is the probability of rolling a 2?

On a street with 7 houses, 2 houses are blue. If a house from this street is selected at random, what is the probability of selecting a house that is blue?

A grove has 6 rows of birch trees and 5 rows of maple trees. Each row of birch trees has 8 trees 20 feet or taller and 6 trees shorter than 20 feet. Each row of maple trees has 9 trees 20 feet or taller and 7 trees shorter than 20 feet. A tree from one of these rows will be selected at random. What is the probability of selecting a maple tree, given that the tree is 20 feet or taller?