Answer:
There were 70 choices for the four locations to apply the new ointment
Step-by-step explanation:
The order in which the locations are chosen is not important. So we use the combinations formula to solve this question.
Combinations formula:
is the number of different combinations of x objects from a set of n elements, given by the following formula.

How many different choices were there for the four locations to apply the new ointment
Four locations from a set of 8. So

There were 70 choices for the four locations to apply the new ointment
The area of this rectangle is x*y. But, this problem requires that you represent the variable "y" in terms of "x" only.
A hint here is that the variable "y" represent a point on the line that connects the end points (0,b) and (a,0).
The first step to solve this problem is to get the expression of this line.
The slope of this line is: m = (0 - b)/(a - 0) = -b/a
Because the point (x,y) is on this line we have: y - b = m(x - 0)
y = (-b/a)x + b
Solution: Area of the rectangle = x*y = x*((-b/a)x + b) = (-b/a)x2 +bx
Known facts:
A line shaft rotating at 250 rpm, a grinder shaft that turns at 1200 rpm diameter of grinder pulley is 5 inches.
1. Proportion equation
350/1200 = 5/x
2. Cross multiply
1200*5=250*x
x=(1200*5)/250 = (24*50*5)/(5*50) = 24
The big wheel diameter is 24 inches
I’m personally not to good at adding fractions so I turned 1/10 into 0.1
Then I divided 268.4 by .1 and got 2,674.