Ametalworker has a metal alloy that is 25% copper and another alloy that is 70% copper. how many kilograms of each alloy should the metalworker combine to create 50 kg of a 61% copper alloy? the metalworker should use nothing kilograms of the metal alloy that is 25% copper and nothing kilograms of the metal alloy that is 70% copper

10 kgs of 25% copper alloy and 40 kgs of 70% copper alloy

Step-by-step explanation:

Let a be kg of 25% copper alloy, and

b be kg of 70% copper alloy

We can write two equations:

1. a + b = 50

2. 0.25a+0.7b=0.61(50)

We can write #1 as b = 50 - a, and then plug it into #2. We have:

0.25a+0.7b=0.61(50)

0.25a+0.7(50 -  a) = 0.61(50)

0.25a + 35 - 0.7a = 30.5

-0.45a = 30.5 - 35

-0.45 a = -4.5

a = -4.5 / - 0.45

a = 10

Also, b = 50 - a, so b = 50 - 10 = 40

The metalworker should use 10 kgs of 25% copper alloy and 40 kgs of 70% copper alloy to make it.

2.2°  

step-by-step explanation:

let θ = the angle of elevation.

tanθ =77/2020

tanθ = 0.038 12

      θ = tan⁻¹0.038 12

      θ = 2.2°