Independent solution

How to solve this Contingency Tables question

Setup

Setup

Let x be the male-nonsmoker count and y the requested female-smoker count.

MN=x,FN=x+100MN=x,\qquad FN=x+100
FS=y,MS=350yFS=y,\qquad MS=350-y

Model

Model

Form the male and female portfolio totals from the four cells.

M=x+350yM=x+350-y
F=x+100+yF=x+100+y

Compute

Compute

Apply the stated excess of male policies over female policies and solve.

x+350y=(x+100+y)+150x+350-y=(x+100+y)+150
100=2y,y=50100=2y,\qquad y=50

Answer

Answer

The number of female-smoker policies is 50.

50(A)\boxed{50\quad\text{(A)}}