5. charlotte is picking out her class ring. she can select from a ruby, an emerald, or an opal stone, and she can also select silver or gold for the metal.
a. how many different combinations of one stone and one type of metal can she choose? explain how you got your answer.
b. if charlotte selects a stone and a metal at random, what is the probability that she would select a ring with a ruby stone and gold metal?

Step-by-step explanation:

Given

Charlotte can select from a ruby , an emerald or an opal stone

i.e. there are 3 choices for stone

while there are 2 choices for metal i.e. silver or gold

no of ways to select a stone is

no of ways to select metal

No of ways to select a ring

(b)Probability of selecting a ruby is

Probability of selecting a metal is

Probability of selecting a ring with a ruby stone and gold metal  

i used to know how to do this in 7th but i forget easily

step-by-step explanation: