Using Proportions
A science teacher chose a girl to pass out tests to the class. If there are 35 students in the class and the probability of choosing a girl is 1/5, how many girls are in the class
What is 7?
What is the probability that Mr. Stricker had a boy?
1/2
Maria is flipping a coin and spinning a spinner. The spinner has 4 equal sections labeled A-D. What is the probability the coin will land on heads and the spinner will land on the letter "A"?
1/8 or 0.125, or 12.5%
Mr. Stricker and Ms. Gustafson are discussing how awesome you are. If Ms. Gustafson received homework from 3/4's of this class, how many scholars turned in homework?
Suppose Joe rolls a 6 sided number cube. If the probability of rolling a number less than 5 is 2/3, what is the best prediction of the number of times Joe will roll less than 5 if he rolls the cube 150 times?
What is 100?
Bob rolls a six sided die and flips a coin, what is the probability he will land on an even number and heads?
3/6x1/2=3/12=1/4
If Sally has 5 pairs of pants, shirts colored red, green, blue, and pink, and shoes that are black or brown, how many outfits can she make?
What is 40?
There were 5 blue marbles and 5 red marbles in a bag. WHat is the probability of getting a blue marble?
5/10 or 1/2
At Frank's Furniture Store, the ratio of sales of living room furniture to bedroom furniture is 3 to 2. If 184 bedroom sets were sold last year, what is the best prediction for the number of living room sets sold last year?
What is 276?
What is the probability that 2 people in this class are sick? How about 5?
2/16 or 5/16
Pedro recorded the types of birds that visit his bird feeder. Based on the results below, what is the probability the next bird will be a chickadee? Woodpecker = 3 Chickadee = 5 Cardinal = 1 Sparrow = 13 Blue Jay = 3
1/5, or 0.20, or 20%
If the weather report calls for a 20% chance of rain, this is the probability it will not rain?
What is 80%?
If you rolled 2 number cubes, what is the probability of rolling a 6 on one and an even number on the other?
What is 1/12?
In a bag of 20 marbles colored black, red, blue, and yellow, 80% of the marbles are black, red, or blue. How many marbles yellow? (not the percent)
What is 4?
The weather man said there is a 10% chance of snow today, if it does not snow it will rain. What is the chance it will rain today?
90%
The cafeteria is serving oranges, bananas and apples today. They also are serving carrots, beans and peas. What is the probability of getting an apple and peas
1/3x1/3=1/9
Describe the difference between events that are certain, likely, equally likely, unlikely, or never going to happen.
Explain
You are trying to decide what to wear to school. You know you have a green pair of pants, a red pair, and a blue pair. You also have a brown shirt, a plaid shirt, and a yellow shirt. How many different outfit combinations can you make?
9