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Jen, Kathy, and Lou work Together. The ratio of Jen's salary to Kathy's salary is 4:3. Lou makes $4,000 more than Kathy does.
If the total of their salaries is $134,000, how much does each person make?
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Mathematical model is this system of equations
= , (1)
K + 4000 = L, (2)
J + K + L = 134000, (3)
or
J = , (4)
K = L - 4000, (5)
J + K + L = 134000. (6)
Express J via L by substituting (5) into (4):
J = . (7)
Now substitute (7) and (5) into (6). You will get a single equation for L:
= 134000.
Multiply both sides by 3:
4*(L-4000) + 3*(L-4000) + 3L = 134000*3 = 402000.
Simplify and solve for L:
10L - 28000 = 402000 -----> 10L = 430000 -----> L = = 43000.
Now you can easily find the rest of unknowns:
K = L - 4000 = 43000 - 4000 = 39000,
J = = = 4*13000 = 52000.
Answer. J = 52000, K = 39000, L = 43000.