A metallurgist has one alloy containing 24% aluminum and another containing 60% aluminum. How many pounds of each alloy must he use to make 44 pounds of a third alloy containing 47% aluminum?

15 8/9 pounds of 24%

28 1/9pounds of 60%

Step-by-step explanation:

x = pounds of 24%

44 - x = pounds of 60%

24x + 60(44  - x) = 47(44)

24x + 2640 - 60x = 2068

-36x + 2640 = 2068

-36x = -572

x = 15 8/9

44 - x = 28 1/9

Rounded

15 8/9 pounds of 24%

28 1/9pounds of 60%

there are lots of ways.   pick's theorem tells us if the vertices are lattice points the area a is

a = b/2 + i - 1

where b is the number of boundary lattice points and i is the number of interior lattice points.

in the figure i count b=16, i=50 so

a = 8 + 50 - 1 = 57

let's try the shoelace formula.   the area is half the sum of the cross products of the sides.  

a(-2,6)   -2(2)-6(-5) = 26

b(-5,2)   -5(-3) - 2(-2) = 19

c(-2,-3) -2(-3) - (-3)(4) = 18

d(4,-3)   4(3) - (-3)(5) = 27

e(5,3)   5(3) - 3(1) = 12

f(1,3)     1(6) - 3(-2) = 12

a(-2,6)

each of the cross products is twice the area of the triangle with the associated side and one vertex the origin. so the area of abo=26/2=13.

area = (1/2) (26 + 19 +   18 + 27 + 12 + 12) = 57

that checks!