First, let x or any variable represent the number of paintings Kate initially has. After selling 12 of it, her paintings now becomes only x - 12. Then, she purchased 7 more making the number of her paintings become x - 12 + 7 = x - 5. This number tantamount to 21.
x - 5 = 21 ; x = 26
Thus, Kate initially had 26 paintings.
Doubling the radius of the cylinder will quadruple the volume.
First of all, you have to find the area of both triangles:


Or just 16 because there are 2 of the same triangles.
Now you have to find the area of the 3 rectangles.
The two that are in the front are 4*3 (l*h) or 12*2 (because there are 2 congruent rectangles. The area of those rectangles is 24 square mm.
Now you find the area of the back rectangle:
5.7*3 = 17.1
Finally, you add all the found numbers to figure out the surface area.
17.1 + 16 + 24 = 57.1 square millimeters.
Hope this helped,
Loafly
Step-by-step explanation:
12,000 views = 4 hours
=> 30,000 views = 4 * (30000/12000) = 10 hours.
Hence it will take 10 hours.