So, The dots represent the children.
And the numbers represent the length in.
I wouldnt say its D.
I would say its C. Group B, because 4 kids have forearm length longer then 13 in.
We're told that



a. We want to find
. By definition of conditional probability,

By the law of total probability,

Then

(the first equality is Bayes' theorem)
b. We want to find
.

since
.
Answer: 7.7 years
Step-by-step explanation:
Given
The cost of HD TV is $700 and it is decreasing at the rate of 15% per year
After one year it becomes

after 2 year it becomes

Suppose, after x years it becomes $200

Thus, it takes 7.7 years for the cost to come under $200.