Question

A box contains 10 red ribbons and 12 blue ribbons. Once a ribbon is picked, it is not replaced. What is the probability of choosing a red then a blue ribbon?

Answer 1

1) Altogether ribbons = 10+12=22
Choosing red  - 10/22.

2) When red is removed we still have 12 blue ribbons, but altogether now we have 9 red +12 blue = 21 ribbons 

Choosing blue - 12/21.

3) Choosing red and then blue   - 10/22*12/21 =5/11*12/21 = 60/231

If you need % then,  (60/231)*100 = 25.97%.

Answer 2

Hello!

There are 22 total ribbons. First of all we have the probability of selecting a red ribbon.

10/22=5/11

Since we took one out without replacing we put the probability out of 21.

12/21

Now we multiply the probabilities.

5/11(12/21)=60/231

I hope this helps!