An alloy weighing 30 lbs. is 11% tin. the alloy was made by mixing a 15% tin alloy and a 9% tin alloy. how many pounds of each alloy were used to make the 11% alloy? lbs. of the 15% alloy and lbs. of the 9% alloy.

We let x = pounds of alloy that is 15% tin

The problem is modeled by the equation:

0.11(30) = 0.15x + 0.09(30-x)

The equation means that the amount of tin does not change. Also, the amount of alloy (total weight - weight of 15% alloy) is (30-x).  

Solving for x:

3.3 = 0.15x +2.7 - 0.09x

.06x = 0.6

x = 10 lbs

30-10 = 20 lbs

10 lbs. of the 15% alloy and 20 lbs. of the 9% alloy

is there a picture

step-by-step explanation:

the multiples of 15 are 15, 30,45, 60, 75, 90, 105, 120, 135, 150, 165, 180, 195,   210, 225, 240, 255, 270, 285, 300, 315, 330, 345, 360, 375,   390, 405, 420, 435, 450, 465, 480, 495, 510, 525, 540, 555, 570, 585, 600, 615, 630, 645, 660, 675, 690, 705, 720, and 735.

the factors of 15 are 1, 3, 5, and 15.

hope that , fam!

-une, your fren : )