Question

As students walk into Mr. Jackson's class, they are randomly handed either a blue, yellow, green, or red card. If there are 8 boys and 12 girls in the class, what is the probability that the student chosen by Mr. Jackson will be a boy with a green card?
A. 1/8  B. 1/16  C. 2/15 D. 1/5

Answer 1

The answer is B 1/16 there are 16 kids in total 

Answer 2

we are given

Event-A:

they are randomly handed either a blue, yellow, green, or red card

so, total number of cards =3

probability of selecting green cards = (number of green card)/(total number of cards)

probability of selecting green cards is $\frac{1}{3}$

Let's assume

$p(A)=\frac{1}{3}$

Event-B:

there are 8 boys and 12 girls in the class

total number of students =8+12=20

number of boys =8

probability of a boy = (number of boys)/(total number of students)

$p(B)=\frac{8}{20}$

Since, events A and B are independent

so,

probability that the student chosen by Mr. Jackson will be a boy with a green card = p(A)*p(B)

probability that the student chosen by Mr. Jackson will be a boy with a green card = $\frac{8}{20} *\frac{1}{3}$

$=\frac{8}{20} *\frac{1}{3}$

$=\frac{2}{15}$

probability that the student chosen by Mr. Jackson will be a boy with a green card is $\frac{2}{15}$...........Answer