We have 60 gallons of 20% antifreeze.
How much 70% antifreeze do we add to get 60% antifreeze?
We'll make "x" the gallons of 70% we must add.
.20 * 60 + .70 x = .60 * (60 + x)
12 + .70x = 36 + .60x
.10x = 24
x = 240 gallons of 70% antifreeze.
Source
1728.com/mixture.htm (see example B)
16. no i dont agree. 1 is the only number that can multiply and equal itself. also, 0.1 is not even a whole number
17. it took 19 to 21 hours. one way to show work is by long division. i dont know how to do another way im so sorry
18. because 15000 is the amount in 50 minutes, so just divide 50 minutes of phones by 50 to get one minute of phones
i am worn out i cant do the last one
158 boys, and 163 girls, do this by dividing 321 by two(do get how many of each gender if #s were equal) subtract 2.5 to get boys, and add 5 to that to get girls
The standard form of the equation of a circle is (x-h)^2 + (y-k)^2 = r^2, where (h,k) is the center of the circle, (x,y) is a point of the circle, and r is the length of the radius of the circle. When the equation of a circle is written, h,k, and r are numbers, while x and y are still variables. (x-2)^2 + (y-k)^2 = 16 is an example of a circle. The problem gives us two of the three things that a circle has, a point (5,9) and the center (-2,3). We need to find the radius in order to write the equation. We substitute -2 for h, 3 for k, 5 for x, and 9 for y to get (5 - (-2))^2 + (9 - 3)^2 = r^2 We simplify: 49 + 36 = r^2, r^2 = 85. We only need to know r^2 because the equation of a circle has r^2. We now have all the information to write the equation of a circle. (x + 2)^2 + (y - 3)^2 = 85.