jmc

Question

There are 30 students in Mrs. Taylor's kindergarten class. If there are twice as many students with blond hair as with blue eyes, 6 students with blond hair and blue eyes, and 3 students with neither blond hair nor blue eyes, how many students have blue eyes?

Accepted Answer

Let the number of blue-eyed students be

x

, so the number of blond students is

2 x

. Since the number of blue-eyed blond students is

6

, the number of blue-eyed non-blond students is

x - 6

, while the number of blond non-blue-eyed students is

2 x - 6

. Since the number of non-blue-eyed non-blond students is

3

, we can add up these four exclusive categories (blond blue-eyed, blond non-blue-eyed, etc.) to sum to 30 students in the class.

So

(x - 6) + (2 x - 6) + 6 + 3 = 30

and

x = 11

, which is the number of blue-eyed students.