Introduction to Probability

A bag contains four red balls, two green balls and one white ball. One ball is picked and put back in, then a second ball is picked. What is the probability of the first ball being red?

• 2/7
• 3/7
• 1/7
• 4/7

A bag contains four red balls, two green balls and one white ball. What is the probability of picking a red ball?

• 3/7
• 1/7
• 2/7
• 4/7

A random letter is chosen from RHOMBUS. What is the probability of choosing a vowel?

• 1/6
• 1/3
• 1/4
• 1/2

A fair dice is rolled. What is the probability of rolling a number greater than 2?

• 1/2
• 1/4
• 1/3
• 2/3

A bag contains three red balls, two blue balls, and one green ball. What is the probability of picking a blue ball?

• 1/2
• 1/3
• 1/6
• 1/4

Two fair dice are rolled. What is the probability of rolling a sum of 7 or 11?

• 1/4
• 1/3
• 1/2
• 1/6

A random letter is chosen from ISOSCELES. What is the probability of choosing the letter C?

• 1/8
• 1/7
• 1/6
• 1/5

A fair dice is rolled. What is the probability of rolling an even number?

• 2/3
• 1/3
• 1/2
• 1/4

A bag contains four red balls, two green balls and one white ball. Two balls are picked out. What is the probability of picking a red ball on the second turn, if the first ball is red and is not replaced?

• 3/6
• 2/7
• 4/7
• 3/7

A fair dice is rolled. What is the probability of rolling a 5 or 6?

• 1/3
• 1/2
• 1/4
• 1/6