a 480 pound alloy containing 30% silver was mixed with an alloy containing 55% silver to get an alloy containing 40% silver. How many pounds of the 55 alloy were used?

Answer 1

Let x be the number of pounds of the 55% silver alloy used.

The amount of silver in the 480 pound alloy is 0.3 * 480 = 144 pounds.

The amount of silver in the x pound alloy is 0.55x.

When the two alloys are mixed, the total amount of silver is 144 + 0.55x.

The total weight of the new alloy is 480 + x pounds.

Since the new alloy contains 40% silver, we can set up the following equation:

0.4(480 + x) = 144 + 0.55x

192 + 0.4x = 144 + 0.55x

0.15x = 48

x = 320 pounds

Therefore, 320 pounds of the 55% silver alloy were used.