Find RK given the following?

Question

Answer 1

First, you should insert the variables you know :

R_KT_K + 60 = R_MT_M

R_K*(3) + 60 = R_M*(2)

We now have 2 equations that relate R_K to R_M. Since we have 2 unknown variables and 2 equations, we can solve by plugging one equation into the other. See the following :

Since you are trying to find R_K, put R_M in terms of R_K :

R_K + R_M = 25

R_M = 25 - R_K

Plug it into the equation we got before :

R_K*(3) + 60 = R_M*(2)

R_K*(3) + 60 = (25 - R_K)*(2)

simplify and solve :

R_K*(3) + 60 = (25 - R_K)*(2)

3*R_K + 60 = 50 - 2*R_K

5*R_K + 60 = 50

5*R_K = -10

R_K = -2

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Always check your work! To do so, solve for R_M first :

R_M = 25 - R_K

R_M = 25 - (-2)

R_M = 27

Plug it all into the original equation :

R_KT_K + 60 = R_MT_M

(-2)*(3) + 60 = (27)*(2)

-6 + 60 = 54

54 = 54

Correct!