you need another equation to solve them simultaneously since they are two unknown
Answer:
The variance for the number of tasters is 4.2
Step-by-step explanation:
For each person, there are only two possible outcomes. Either they are tasters, or they are not. The probability of a person being a taster is independent of any other person. So we use the binomial probability distribution to solve this question.
Binomial probability distribution
Probability of exactly x sucesses on n repeated trials, with p probability.
The variance of the binomial distribution is:

It is known that 70% of the American people are "tasters" with the rest are "non-tasters". Suppose a genetics class of size 20
This means that 
So

The variance for the number of tasters is 4.2
Answer:
A.102%
Step-by-step explanation:
Let cost price of painting=$100
In first year price increased 20%
Then , the price=
$120
In second year
Price decreased 15%
Then , the price of painting=
The price of painting=$102
Percent =
By using this formula
Then, we get
Percent of the original price=
Percent of the original price=102%
Option A is true.
The answer could be 45 but I'm not entirely sure