I'm asuming you did a typo from a previous quesiton I see that it is a dollar sign
$12 per hour
for 15 hourse, just multiply $12 by 15 because per hour means per 1 hour
15 times $12=$180
answer is $180
4 °C
i just googled it XD. source: https://www.google.com/search?q=the+density+of+water+is+maximum+at+which+temperature&oq=the+density+of+water+is+maximum+at+which+temperature&aqs=chrome..69i57.699j0j4&client=ms-android-samsung&sourceid=chrome-mobile&ie=UTF-8
Add 4.5<span> and </span>9.2<span> to get </span><span>13.7.
</span>13.7
13.7 in. is the length
Answer:
the total amount of water supplier per hour to the region within a circle of radius R=110 ( that is from distance r, 0<r<110)
![W(R) = 2\pi [1-(R+1)e^{-R}]](https://tex.z-dn.net/?f=W%28R%29%20%3D%202%5Cpi%20%5B1-%28R%2B1%29e%5E%7B-R%7D%5D)
Step-by-step explanation:
if f(r) describes the water supplied at a distance r , the total amount supplied inside a region that goes from 0 until the circle of radius R, is the sum of all f(r) values from 0 until R, that is the integral value over these limits.
The formula deduction can be found in the attached picture
There is an "r" that multiplies e^-r as result of changing from rectangular coordinates to polar ones.(dx*dy --> r*dr*da)