You can put this solution on YOUR website! when one-third of a number is added to one-fourth of the number, the sum is 21. what is the number?
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Let the number be "x":
(1/3 + 1/4)x = 21
[(4+3)/12]x = 21
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(7/12)x = 21
x = 12*21/7
x = 36
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Cheers,
Stan H.