Answer:
In fifteen years, Alexis would have 9200. In twenty years she would have 9600
Step-by-step explanation:
10% for interest of 8000= 80.
80 (interest for one year) * 15 (fifteen years)= 1200
1200 plus the original amount is 9200.
80 (interest for one year) * 20 ( twenty years)= 1600
1600 plus the original amount is 9600
let's label each pump A, B, and C, just for convenience. A fills the tank by 1/50 every minute, B fills the tank by 1/60 every minute, and C drains it by 1/75 every minute. Now we can put them all into one function: t(1/50 + 1/60 - 1/75) = 1, where t = our time in minutes and 1 = the tank being full.
next, we solve for t: t = 300/7 minutes, or approximately 42.86 minutes.
Answer:
(0, -3)
Step-by-step explanation:
Here we'll rewrite x^2+y^2+6y-72=0 using "completing the square."
Rearranging x^2+y^2+6y-72=0, we get x^2 + y^2 + 6y = 72.
x^2 is already a perfect square. Focus on rewriting y^2 + 6y as the square of a binomial: y^2 + 6y becomes a perfect square if we add 9 and then subtract 9:
x^2 + y^2 + 6y + 9 - 9 = 72:
x^2 + (y + 3)^2 = 81
Comparing this to the standard equation of a circle with center at (h, k) and radius r,
(x - h)^2 + (y - k)^2 = r^2. Then h = 0, k = -3 and r = 9.
The center of the circle is (h, k), or (0, -3).
