A metalworker has a metal alloy that is 30% copper and another alloy that is 65% copper. How many kilograms of each alloy should the metalworker combine to create 80kg of a 51% copper alloy?

Step-by-step explanation:

If x is the mass of 30% copper alloy, and y is the mass of 65% copper alloy, then:

x + y = 80

0.30x + 0.65y = 0.51(80)

Solving the system of equations using substitution:

0.30x + 0.65(80 − x) = 0.51(80)

0.30x + 52 − 0.65x = 40.8

11.2 = 0.35x

x = 32

y = 80 − x

y = 48

The metalworker needs 32 kg of 30% copper alloy and 48 kg of 65% copper alloy.

14.3

step-by-step explanation:

add all the numbers together.

9 + 12 + 15 + 16 + 17 + 17 = 86

now, divide 86 by how many numbers we have: 6.

86 / 6 = 14.3

answer: 0

step-by-step explanation: the positive, like 5, + its opposite, like -5 would be 0

5+(-5)=0, or 5-5=0