All PSAT Math Resources
Example Questions
Example Question #53 : Probability
A coin with two sides, heads and tails, is flipped repeatedly and the result recorded. Assuming an equal chance of it landing either way, what is the probability of each of the first four flips being heads?
Example Question #3132 : Sat Mathematics
A coin with two sides, heads and tails, is flipped 10 times and the results recorded. What is the probability that the 10th flip results in tails?
Example Question #54 : Probability
A dresser drawer contains only 4 blue socks, 6 white socks, and 2 red socks. If two socks are pulled from the drawer at random, what is the probability that they are both white?
For this question to be satsified, both socks drawn must be white.
First draw: 6 white socks out of 12 total:
Second draw: 5 white socks out of 11 total:
Multiply together to find the answer:
Example Question #53 : Probability
In a hotel with 120 rooms, 30 of them have red carpet. A hotel manager has lost his keys somewhere in the hotel. If there is an equal chance of the keys being in any room, what is the probability that they are in a room with red carpet?
Probability = desired outcomes divided by total possible outcomes
Example Question #53 : Probability
A bag contains the following numbers of apples: 12 red delicious, 10 granny smith, and 7 fuji apples. If an apple is selected at random, what is the probability it is either a granny smith or a fuji apple?
Probability = desired outcomes divided by total possible outcomes. Desired outcome can be either fuji or granny smith.
Desired outcomes
Total outcomes
Example Question #54 : Probability
From a class consisting of 15 girls and 12 boys, two students are chosen at random to be class representatives. What is the probability that neither of the two students chosen is a boy?
To satisfy the question, BOTH students chosen must be girls.
First selection: 15 girls of 27 total students:
Second selection: 14 girls out of 26 total students:
Example Question #61 : How To Find The Probability Of An Outcome
If 2 six-sided dice, each with sides numbered 1-6, are rolled, what is the probability that the sum of the numbers on the face-up sides is equal to 7?
Probability = desired outcomes divided by total possible outcomes.
Desired outcomes = 6 (1,6; 2,5; 3,4; 4,3; 5,2; 6;1)
Total outcomes - 36
Example Question #54 : Probability
If an 8-sided die is rolled 3 times, what is the probability that the same number will be rolled each time?
Another way to look a it is there are 512 total possible outcomes and 8 desired outcomes.
Example Question #61 : How To Find The Probability Of An Outcome
If a two-sided coin is flipped four times, what is the probability of never getting a head?
The probability of never getting a head is the same as always getting tails. This is .
Example Question #62 : How To Find The Probability Of An Outcome
If a six-sided die is thrown four times, what is the probability of getting a four everytime?
The probability is .