How do I solve this basic word math equation

"The average yearly salary of an American whose finial degree is a master's is $49 thousand less than twice of that of an American whose final degree is a bachelor's. Combined, two people with each of these educational attainments earn $116 thousand. Find the average yearly salary of Americans with each of these final degrees."

I have the answer, but I just don't understand how that is the correct answer..
THE ANSWER: Bachelor's: $55 thousand, Master's: $61 thousands
Can you please explain it if you understand THANKS

let m = salary of person with master's degree, b = bachelor's.

m = 2b - $49,000 and m + b = $116000 (rewritten, this is m = $116000 - b)
so we can say that they're equal to each other (m = and m =)
2b-49000=116000-b
add b to both sides and 49000 to both sides
3b = 165000
b=55,000
m=116000-b=116000-55000
m=61000

m = 2b - 49
m + b = 116
substitute the first equation into the second equation:
2b - 49 + b = 116
3b - 49 = 116
3b = 165
b = 165/3 = $55 thousand
using the first equation:
m = 2(55) - 49 = $61 thousand

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You have to set up two different equations using the info they give

M=2B-49

and

M + B = 116

so in the second equation, substitute 2B-49 for M

2B - 49 + B = 116

3B -49 = 116

3B = 165

B = 55

2 * BS - 49K = MS

BS + MS = 116K

this is a system of equations ... we can solve by substitution...

BS + MS = 116K
BS = 116K - MS
now substitute
2 * BS - 49K = MS
2 * (116K - MS) - 49K = MS
232K - 2MS -49K = MS
183K - 2MS = MS
183K = 3MS
61k = MS

if an MS is 61K then what is the BS?
BS + MS = 116K
BS + 61K = 116K
BS = 55K