Question

There are 20 girls and 15 boys in a class. 1/5 of the girls and 2/5 of the boys bring their lunch from home. One of the students who brings lunch from home is chosen at random. Find the probability that the student is a girl.

• A. 1/3
• B. 2/3
• C. 1/2
• D. 2/5
• E. 1/4

Hint:

Break probability questions into steps: find favorable outcomes, total outcomes, then divide.

Answer 1

The Correct Option is D

Step 1: Count the number of girls bringing lunch.
Total girls = 20
Girls bringing lunch = \( \frac{1}{5} \times 20 = 4 \)
Step 2: Count the number of boys bringing lunch.
Total boys = 15
Boys bringing lunch = \( \frac{2}{5} \times 15 = 6 \)
Step 3: Total students bringing lunch.
\[ 4 + 6 = 10 \] Step 4: Probability that the selected student is a girl.
\[ \frac{\text{Girls bringing lunch}}{\text{Total students bringing lunch}} = \frac{4}{10} = \frac{2}{5} \] Step 5: Conclusion.
Thus, the probability that the selected student is a girl is \( \frac{2}{5} \).