Half the pupils in Mrs. Cross's class are boys. Half the boys have blue eyes. Half the blue-eyed boys have blond hair. There are three boys with blue eyes and blond hair in Mrs.Crooss's class. How many pupils are there total in that class.

Question

Half the pupils in Mrs. Cross's class are boys. Half the boys have blue eyes. Half the blue-eyed boys have blond hair. There are three boys with blue eyes and blond hair in Mrs.Crooss's class. How many pupils are there total in that class.

Answer 1

"There are three boys with blue eyes and blond hair in Mrs.Cross's class."

Start with 3.

"Half the blue-eyed boys have blond hair."

So the above number of 3 only represents half of the blue-eyed boys.

So, there are 2*3 blue-eyed boys total, which is 6.

"Half the boys have blue eyes."

Now we can determine that there are 6*2 boys total.

Try to determine how many pupils are in the class.

Answer 2

Let's break down the information given step by step:

Step 1: Half the pupils in Mrs. Cross's class are boys.
Step 2: Half the boys have blue eyes.
Step 3: Half the blue-eyed boys have blond hair.

From the given information, we know that there are 3 boys with blue eyes and blond hair in Mrs. Cross's class.

Let's calculate the number of blue-eyed boys in the class:

Since half the boys have blue eyes (Step 2), we can multiply the number of blue-eyed boys by 2 to calculate the total number of boys in the class. Therefore, 3 boys with blue eyes and blond hair multiplied by 2 equals 6 blue-eyed boys in total.

Since half the blue-eyed boys have blond hair (Step 3), we can multiply the number of blue-eyed boys by 2 to calculate the total number of blue-eyed boys with blond hair. Therefore, 6 blue-eyed boys multiplied by 2 equals 12 blue-eyed boys with blond hair in total.

Since half the pupils in Mrs. Cross's class are boys (Step 1), we can multiply the number of blue-eyed boys with blond hair by 2 to calculate the total number of pupils in the class. Therefore, 12 blue-eyed boys with blond hair multiplied by 2 equals 24 total pupils in Mrs. Cross's class.

Therefore, there are 24 pupils total in Mrs. Cross's class.

Answer 3

To find the total number of pupils in Mrs. Cross's class, we can work backwards using the information given.

Let's start with the number of boys with blue eyes and blond hair, which is three. We know that half of the blue-eyed boys have blond hair, so if three boys have blond hair, then there must be six blue-eyed boys in total.

Since half of the pupils are boys, the total number of pupils must be twice the number of boys. Therefore, the total number of pupils in Mrs. Cross's class is 2 * 6 = 12.

So, there are 12 pupils in Mrs. Cross's class.