Events are mutually exclusive only if they cannot both be true.
Only C is alright.
4 is a multiple of two so it can't be right.
Same logic works for B.
And then 2 is prime so then D is out too.
To find the best deal find the unit rate.
City express unit rate for pants per dollars is 1 pair : $20.33
Denim Planet unit rate is 1 pair : $36.50
New Threads Unit rate is 1 pair : $27.50
So City Express is the best deal
The area of an equilateral triangle of side "s" is s^2*sqrt(3)/4. So the volume of the slices in your problem is
(x - x^2)^2 * sqrt(3)/4.
Integrating from x = 0 to x = 1, we have
[(1/3)x^3 - (1/2)x^4 + (1/5)x^5]*sqrt(3)/4
= (1/30)*sqrt(3)/4 = sqrt(3)/120 = about 0.0144.
Since this seems quite small, it makes sense to ask what the base area might be...integral from 0 to 1 of (x - x^2) dx = (1/2) - (1/3) = 1/6. Yes, OK, the max height of the triangles occurs where x - x^2 = 1/4, and most of the triangles are quite a bit shorter...
Answer is $924. First you must multiply 1200 by .3 for the sales tax. Giving you 360. You subtract 360 from 1200 giving you 840. Then you multiple 840 by .1 which gives you 84. You then add 84 to 840 giving you $924.