Question

Reyna has 5 coins worth 10 cents each and 4 coins

Answer 1

Answer:

The Probability found is:

P =  $\frac{13}{18}$

Step-by-step explanation:

Let x be the 10 cents coin.

Let y be the 25 cents coin.

We have to find all the possible outcomes

1) First coin = 10 cents, Second coin = 10 cents , so

(x,x) = 20

2) First coin = 10 cents, Second coin = 25 cents , so

(x,y) = 35

3) First coin = 25 cents, Second coin = 10 cents , so

(y,x) = 35

4) First coin = 25 cents, Second coin = 25 cents , so

(y,y) = 50

Find the probability of each outcome:

P(x,x) =  $\frac{5}{9}\cdot\frac{4}{8}=\frac{20}{72}$

P(x,y) =  $\frac{5}{9}\cdot\frac{4}{8}=\frac{20}{72}$

P(y,x) =  $\frac{5}{9}\cdot\frac{4}{8}=\frac{20}{72}$

P(y,y) = $\frac{4}{9}\cdot\frac{3}{8}=\frac{12}{72}$

Add all the probabilities where sum is at least 35 i.e P(x,y) , P(y,x) , P(y,y)

P(x,y) + P(y,x) + P(y,y) = $\frac{20}{72}+\frac{20}{72}+\frac{12}{72} = \frac{52}{72}=\frac{13}{18}$