SOLUTION: Set up an inequality and solve it. Be sure to label clearly what the variable represents. If three-fourths of a number is 21 less than two-fifths of the number, what is the number?
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-> SOLUTION: Set up an inequality and solve it. Be sure to label clearly what the variable represents. If three-fourths of a number is 21 less than two-fifths of the number, what is the number?
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Question 362079: Set up an inequality and solve it. Be sure to label clearly what the variable represents. If three-fourths of a number is 21 less than two-fifths of the number, what is the number? Answer by checkley77(12844) (Show Source):
You can put this solution on YOUR website! 3/4X=2/5x-21
3X/4=2X/5-21
3X/4-2X/5=-21
(5*3X-4*2X)/4*5=-21
(15X-8X)/20=-21
7X/20=-21 CROSS MULTIPLY.
7X=-21*20
7X=-420
X=-420/7
X=-60 ANS.
PROOF:
3/4*-60=2/5*-60-21
-180/4=-120/5-21
-45=-24-21
-45=-45
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