ElectricPavlov

Like     4+4      3+3+2      4 + 2 + 2       2+2+2+2    ?

x = y^2 -8y + 13     this is a sideways parabola

    the y value of the vertex is found by   = b / 2a   where   a = 1  and   b = -8

      use this value of y in the equation to find the x coordinate of the vertex

Over a distance of 2    (from 1 to 3)

   the graph changes from -2  to 4    a change of 6

      average = 6/2 = 3 per unit

2 x4

2*3*4 / 3

4² /2

(4*3)/ (3/2)                  Is that what you mean?

Volume = l x w x h      l = m    h = 3m   w = 4h = 4(3m) = 12m

m   x   3m    x  12m =   36m³

A     salt =  40% * 600 = 240 g

B     salt     20% * 400 = 80 gm

There will be  1000 gm of salt solution at the end of mixing

240g + 80 g    = 1000 (x%)

320 = 1000 x       final solution will be 32%

Let 'x' be the amount to pour off of the 4% solution     this will be the same amount of 2% solution to be added back in to make 600 gm of 32%

.4 (600-x)  + .2(x) = 600 (.32)

x=240 ml

pour off 240 ml from each and add it to the other ..... you will have 600 gm of 32%    and  400gm of 32%

Way to go, CP !

x is given as  -6y + 7    put THIS value of 'x' into the FIRST equation

2 (-6y+7) - 9y = 14

-12y + 14 - 9y = 14

-21y = 0

    y = 0               Use this value of y in one of the equations to find the 'x' value

Sorry.....when  hit 'post answer'    I saw an error that I quickly edited....but you must have originally read the first version before I got my quick edit in there !     Usually I highlight edits, but this was a quick one.....but YOU were quicker !  

When Ruth originally drains water    200 out of 1000 is water   2/10

   2/10 of 100 drained  is   20   which leaves  180 ml

       add   100 ml   =   280 ml of water now in beaker of 1000 ml      280/1000 =  7/25 is water

           draining 100   removes   7/25 x 100 = 28

                     280 - 28 = 252 ml

              then she adds another 100 ml water     252 + 100 = 352 ml water in final solution