The sum of the ages of john and mary is 32. 4 yrs ago, joh was twice as old as mary. find the present age of each.

Make two equations for j = john and m = mary.

j + m = 32

j - 4 = 2m

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Solve for m in the first equation. Subtract j from both sides.

m = 32 - j

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Plug m into the second equation.

j - 4 = 2(32 - j)

Distribute 2 inside the parentheses.

j - 4 = 64 - 2j

Add 4 to both sides.

j = 68 - 2j

Add 2j to both sides.

3j = 68

Divide both sides by 3.

j = 22 2/3

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Plug j into the first equation.

22 2/3 + m = 32

Subtract 22 2/3 from both sides.

m = 9 1/3

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Mary =

John =

13.46

step-by-step explanation:

16.80 x .20 = 13.46