In a deck of lotteries, there are 10 prizes and 25 blanks. A lottery is drawn at random. What is the probability of getting prize?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → \(\frac{2}{7}\)
Every lottery ticket is equally likely to be drawn, so the probability of a prize is the number of prizes divided by the total number of tickets (prizes and blanks together).
Total number of tickets \(=10+25=35\)
Probability of a prize \(\displaystyle=\frac{10}{35}=\frac{2}{7}\)
Tip: Divide by all the tickets, not by the blanks: \(\frac{10}{25}\) is the ratio of prizes to blanks, not a probability.