How many gallons of a 65 % sugar solution do we need to mix with
114 gallons of a 40 % sugar solution, so that the resulting mixture is a
46 % sugar solution?

You would need 36 gallons of 65% sugar solution

Step-by-step explanation:

You can always solve these problems with a proportion

The numerator will represent the amount of sugar, the denominator will represent the amount of solution.

First, we have (.4 * 114 = ) 45.6 gallons of sugar.

10 * 563.67 = 5636.7

the value of v.w= -12.

step-by-step explanation:

we are given three vector r,v and w as:

r = < 5, -5, -2> ; v = < 2, -8, -8> ; w = < -2, 6, -5>

we know that r,v and w could also be represented as:

r=5i-5j-2k

v=2i-8j-8k

and w= -2i+6j-5k

where i,j and k are the unit vectors of x,y and z-axis respectively.

also we know that it has the following property:

i.i=1 ; j.j=1; k.k=1

and i.=j.i=i.k=k.i=j.k=k.j=0

i.e. when we multiply two vectors or we find it's dot product we need to only multiply the components of x coordinates with each other; y with each other and z with each other.

hence, v.w= (2i-8j- -2i+6j-5k)

                  = 2×(-2)+(-8)×(6)+(-8)×(-5)

                  = -4-48+40

                  = -12

hence, v.w= -12