Bytelearn - cat image with glassesAI tutor

Welcome to Bytelearn!

Let’s check out your problem:


Each time she throws a dart, the probability that Mary hits the dartboard is 
(2)/(7).
She throws two darts, one after the other.
What is the probability that she hits the dartboard with both darts?
(A) 
(1)/(21)
(B) 
(4)/(49)
(C) 
(2)/(7)
(D) 
(4)/(7)

Each time she throws a dart, the probability that Mary hits the dartboard is \newline27\frac{2}{7}.\newlineShe throws two darts, one after the other.\newlineWhat is the probability that she hits the dartboard with both darts?\newline(A) 121\frac{1}{21}\newline(B) 449\frac{4}{49}\newline(C) 27\frac{2}{7}\newline(D) 47\frac{4}{7}

Full solution

Q. Each time she throws a dart, the probability that Mary hits the dartboard is \newline27\frac{2}{7}.\newlineShe throws two darts, one after the other.\newlineWhat is the probability that she hits the dartboard with both darts?\newline(A) 121\frac{1}{21}\newline(B) 449\frac{4}{49}\newline(C) 27\frac{2}{7}\newline(D) 47\frac{4}{7}
  1. Multiply probabilities: Since the events are independent, multiply the probability of hitting the dartboard on the first throw by the probability of hitting it on the second throw. \newlineP(both darts hit)=P(first dart hits)×P(second dart hits)P(\text{both darts hit}) = P(\text{first dart hits}) \times P(\text{second dart hits})
  2. Substitute given probabilities: Substitute the given probability for each dart.\newlineP(both darts hit)=(27)×(27)P(\text{both darts hit}) = \left(\frac{2}{7}\right) \times \left(\frac{2}{7}\right)
  3. Calculate product: Calculate the product. P(both darts hit)=449P(\text{both darts hit}) = \frac{4}{49}
  4. Check answer choices: Check the answer choices to match the calculated probability.\newlineThe correct answer is (B) 449\frac{4}{49}.

More problems from Find probabilities using the addition rule