document.write( "Question 1170974: Three friends A, B and C dine out and decide to split the bill according to what they order. A's portion and B's protion of the bil totalled $35, while B's portion was $5 less than C's portion of the bill. The ratio of A's portion to C's portion of the bill is 4:5. Determine the total bill amount? \n" ); document.write( "
Algebra.Com's Answer #795837 by math_tutor2020(3817)\"\" \"About 
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\n" ); document.write( "A = friend A's portion
\n" ); document.write( "B = friend B's portion
\n" ); document.write( "C = friend C's portion
\n" ); document.write( "A,B,C are positive real numbers and are values in dollars.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"A's portion and B's protion of the bil totalled $35\"
\n" ); document.write( "So,
\n" ); document.write( "A+B = 35\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"B's portion was $5 less than C's portion\"
\n" ); document.write( "means that
\n" ); document.write( "B = C - 5\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Go back to the first equation. Plug in B = C-5. Isolate C.
\n" ); document.write( "A+B = 35
\n" ); document.write( "A+C-5 = 35
\n" ); document.write( "A+C = 35+5
\n" ); document.write( "A+C = 40
\n" ); document.write( "C = 40-A\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "The ratio of A to C is 4:5, which means,
\n" ); document.write( "A/C = 4/5
\n" ); document.write( "5A = 4C .... cross multiply
\n" ); document.write( "5A = 4(40-A) .... plug in C = 40-A
\n" ); document.write( "5A = 160-4A
\n" ); document.write( "5A+4A = 160
\n" ); document.write( "9A = 160
\n" ); document.write( "A = 160/9
\n" ); document.write( "A = 17.7777777777778 .... which is approximate
\n" ); document.write( "A = 17.78 .... rounding to two decimal places\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "With this value of A, we can then find:
\n" ); document.write( "C = 40-A
\n" ); document.write( "C = 40-17.78
\n" ); document.write( "C = 22.22\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "And,
\n" ); document.write( "B = C - 5
\n" ); document.write( "B = 22.22 - 5
\n" ); document.write( "B = 17.22\r
\n" ); document.write( "
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\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "In summary, we found:
\n" ); document.write( "A's portion = $17.78
\n" ); document.write( "B's portion = $17.22
\n" ); document.write( "C's portion = $22.22\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "This means,
\n" ); document.write( "Total Bill = A+B+C = 17.78+17.22+22.22 = 57.22 dollars\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Answer:
\n" ); document.write( "Total Bill = $57.22
\n" ); document.write( "
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