You just add the values for volunteers that worked 16-20 hours and 21-25 hours which would be 50 + 10 = 60. So the total number of volunteers that workers more than 15 hours is 60.
Let x = number of long sleeve shirts
Let y = number of short sleeve shirts
x + y = 200
x/2 + y/3 = 80
Now solve this pair of simultaneous equations to find x and y.
I find it easiest to use slope-intercept form, or y=mx+b, to do this.
First, find the slope. 6/3 = 2/1 = 2. m = 2.
Next, find the y-intercept. In this case they gave it to you directly. b = -3.
So, the equation would be y = 2x - 3.
The surface area of the object above can be calculated by summing up all the areas of the surfaces. Therefore, we will have 5 surfaces with rectangles as the shape. The volume would be the product of the length, width and the depth. We calculate as follows:
SA = 2(depth)(length) + 2(depth)(width) + (width)(length)
SA = 324 yd^2
VOlume = 30x10x.3
Volume = 90 yd^3
