A couple decides to keep having children until they have a boy, at which point they will stop having children. They also agree to having a maximum of three children. The table below shows the probability
distribution of X = the number of children such a couple would have.
X = # of children

On average, how many children would such a couple have?
E(X)=
children

How are we suppose to know this

You need to figure out at which x-value does the graph has a tangent line slope of -1.remember, the derivative is the slope of the tangent line. so find the derivative function and set it to equal -1 to find the x-value that will have a tangent line slope of 0.differentiate with the chain rule.    set the derivative to equal -1 and solve for x.      take log base 10 of both sides. also recall that  .    so the x-coord of the point of tangency is .the y-coordinate of this point of tangency can be calculated using the original function:     using point-slope form, the equation of the tangent line is      the x-intercept of this tangent line is when the graph is at y=0.    this rounds off to  .choice c.

answer:

ok sir

explanation: