Question

The ratio of boys to girls in a class is 2:3. If there are 18 girls in the class, what is the probability of a boy being in the class, P(boy)? SHOW WORK to verify your choice.

Answer 1

Answer:

0.4

Step-by-step explanation:

If the ratio of boys to girls in a class is 2:3, then

• there are 2x boys;
• there are 3x girls.

If there are 18 girls in the class, then

$3x=18\\ \\x=6$

Thus, there are

• $2\cdot 6=12$ boys;
• $3\cdot 6=18$ girls;
• $12+18=30$ students in total.

The probability of a boy being in the class is

$P=\dfrac{12}{30}=\dfrac{2}{5}=0.4$