document.write( "Question 1196802: If a number of two digits is divided by the sum of its digits, the quotient is 4 and the remainder is 6. If 9 is added to the number the sum has the same digits but inverted. What is the number? \n" ); document.write( "
Algebra.Com's Answer #829803 by math_tutor2020(3817)\"\" \"About 
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\n" ); document.write( "Answer: 34\r
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\n" ); document.write( "\n" ); document.write( "Explanation:\r
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\n" ); document.write( "\n" ); document.write( "a = tens digit
\n" ); document.write( "b = units digit
\n" ); document.write( "Each 'a' and b value is selected from the set {0,1,2,3,4,5,6,7,8,9} where repeats are possible.\r
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\n" ); document.write( "\n" ); document.write( "The two digit number is of the form 10a+b
\n" ); document.write( "For example, if a = 7 is the tens digit and b = 5 is the units digit, then 10a+b = 10*7+5 = 75\r
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\n" ); document.write( "\n" ); document.write( "Divide this over the sum of the digits a+b and we get a quotient of 4 and remainder 6\r
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\n" ); document.write( "\n" ); document.write( "(10a+b)/(a+b) = 4 remainder 6
\n" ); document.write( "(10a+b)/(a+b) = 4 + 6/(a+b)
\n" ); document.write( "10a+b = 4(a+b) + 6\r
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\n" ); document.write( "\n" ); document.write( "Let's solve for b
\n" ); document.write( "10a+b = 4(a+b) + 6
\n" ); document.write( "10a+b = 4a+4b + 6
\n" ); document.write( "b-4b = 4a+6-10a
\n" ); document.write( "-3b = -6a+6
\n" ); document.write( "b = (-6a+6)/(-3)
\n" ); document.write( "b = 2a-2\r
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\n" ); document.write( "\n" ); document.write( "If 9 is added to the original number 10a+b, then we're told the digits swap.\r
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\n" ); document.write( "\n" ); document.write( "original + 9 = swapped digits
\n" ); document.write( "(10a+b) + 9 = 10b+a\r
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\n" ); document.write( "\n" ); document.write( "Now plug in b = 2a-2 and solve for 'a'
\n" ); document.write( "(10a+b) + 9 = 10b+a
\n" ); document.write( "(10a+2a-2) + 9 = 10(2a-2)+a
\n" ); document.write( "12a+7 = 20a-20+a
\n" ); document.write( "12a+7 = 21a-20
\n" ); document.write( "12a-21a = -20-7
\n" ); document.write( "-9a = -27
\n" ); document.write( "a = -27/(-9)
\n" ); document.write( "a = 3\r
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\n" ); document.write( "\n" ); document.write( "Lastly, let's find b
\n" ); document.write( "b = 2a-2
\n" ); document.write( "b = 2*3-2
\n" ); document.write( "b = 6-2
\n" ); document.write( "b = 4\r
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\n" ); document.write( "\n" ); document.write( "The original number is 10a+b = 10*3+4 = 34\r
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\n" ); document.write( "\n" ); document.write( "Let's divide this over the sum of the digits a+b = 3+4 = 7
\n" ); document.write( "34/7 = 4 remainder 6
\n" ); document.write( "So far so good\r
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\n" ); document.write( "\n" ); document.write( "Side note: you can think of it like you have 34 cookies and 7 friends to pass them out to.
\n" ); document.write( "Each friend gets 4 cookies so 7*4 = 28 cookies are taken so far.
\n" ); document.write( "That means there are 34-28 = 6 cookies leftover.\r
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\n" ); document.write( "\n" ); document.write( "Now add 9 to the number
\n" ); document.write( "34+9 = 43
\n" ); document.write( "and the digit swap part is confirmed as well.\r
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\n" ); document.write( "\n" ); document.write( "The answer is fully confirmed.
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