Answer:

Step-by-step explanation:
From the question we are told that
Consumers seen the soap 
Consumers used the soap 
Consumers seen/tried the soap 
Generally the probability that consumers have seen and tried the soap is



Answer:
D
Step-by-step explanation:
I hope this is correct and have a great day
You can make the equation 12x=156-x
Then from there it become 13x=156
So x=12
He would have 21 before he bought the 10 stamp because 31-10=21