SOLUTION: The product of Mary's age in years on her last birthday and her age now in complete months is 1800. How old was Mary on her last birthday?
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You can put this solution on YOUR website! The product of Mary's age in years on her last birthday and her age now in complete months is 1800.
How old was Mary on her last birthday.
Let x = her age on her last birthday in yrs
then
12x = her age in months on her last birthday
:
let m = number of months from her last birthday. (her present age)
then
12x + m = her present age in months
:
x * (12x + m) = 1800
12x^2 + mx = 1800
mx = -12x^2 + 1800
m =
m = -12x +
only integer solution that makes sense
x=12 yrs on last birthday, then m = 6 months
Present age: 12*12 + 6 = 150 months
:
Check
age last birthday: 12 yrs, present age 150 months; 12 * 150 = 1800
