Probability
Independent Events — With Replacement
nta_pyq_2024_jan
Grade 12
Question:
Two marbles are drawn in succession from a box containing 10 red, 30 white, 20 blue and 15 orange marbles, with replacement being made after each drawing. Then the probability that first drawn marble is red and second drawn marble is white, is
$\dfrac{2}{25}$
$\dfrac{4}{25}$
$\dfrac{2}{3}$
$\dfrac{4}{75}$
Step-by-Step Solution
Key Concept: Total $=75$. $P(\text{red})=10/75=2/15$. $P(\text{white})=30/75=2/5$. With replacement, events independent.
$P=\frac{10}{75}\times\frac{30}{75}=\frac{4}{75}$.
Correct Answer: 4