Question

Kaylie wants to see how metals can be combined. She found a problem to solve. Help her solve it! How many pounds of a metal containing 20% nickel must be combined with 6 pounds of a metal containing 80% nickel to form an alloy containing 60% nickel?

PLEASE HURRY AND SHOW YOUR WORK
A. 5 pounds
B. 4 pounds
C. 3 pounds
D. 2 pounds

Answer 1

C. 3 pounds

Explanation:

to use % as factors we need to represent them as what they are : parts of 100.

so, e.g. 20% = 0.2 and so on.

x = pounds of the metal with 20% nickel.

0.2x + 0.8×6 = 0.6×(x + 6) = 0.6x + 3.6

0.2x + 4.8 = 0.6x + 3.6

1.2 = 0.4x

x = 1.2/0.4 = 3

she needs to combine 3 pounds of metal with 20% nickel with 6 pounds with 80% nickel to get 9 pounds (3+6) of an alloy with 60% nickel.