document.write( "Question 1172306: Hi
\n" ); document.write( "Bob spent 50 dollars on pens and markers. The ratio of money spent on pens pencils and markers was 4:5:1. Pens were sold at 3 for a dollar. The number of pencils he bought was 1/6 of the number of pens. The number of markers he bought was 2/5 of the number of pencils.
\n" ); document.write( "How many pens and markers did he buy.
\n" ); document.write( "How many pencils could he buy for 175 dollars. Thanks
\n" ); document.write( "

Algebra.Com's Answer #797300 by math_tutor2020(3816)\"\" \"About 
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\n" ); document.write( "Let's break up the problem into these known facts:
  • Fact 1: Bob spent 50 dollars on pens and markers.
  • Fact 2: The ratio of money spent on pens pencils and markers was 4:5:1.
  • Fact 3: Pens were sold at 3 for a dollar.
  • Fact 4: The number of pencils he bought was 1/6 of the number of pens.
  • Fact 5: The number of markers he bought was 2/5 of the number of pencils.
Let x be some positive real number.
\n" ); document.write( "Fact 2 says the ratio of money spent on pens, pencils and markers is 4:5:1.
\n" ); document.write( "This means
\n" ); document.write( "4x dollars spent on pens
\n" ); document.write( "5x dollars spent on pencils
\n" ); document.write( "1x dollars spent on markers
\n" ); document.write( "The ratio 4x:5x:1x reduces to 4:5:1\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "So we have
\n" ); document.write( "4x+1x = 5x dollars
\n" ); document.write( "spent on pens and markers.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "From fact 1, we know this figure is 50 dollars. So,
\n" ); document.write( "5x = 50
\n" ); document.write( "5x/5 = 50/5
\n" ); document.write( "x = 10\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "With this x value, we find that:
\n" ); document.write( "4x = 4*10 = 40 dollars spent on pens
\n" ); document.write( "5x = 5*10 = 50 dollars spent on pencils
\n" ); document.write( "1x = 1*10 = 10 dollars spent on markers\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "40+50+10 = 100 dollars was spent overall\r
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\n" ); document.write( "\n" ); document.write( "----------------------------------------\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Pens were sold at 3 for a dollar (fact 3)\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "We can form these series of equations
\n" ); document.write( "3 pens = 1 dollar
\n" ); document.write( "6 pens = 2 dollars
\n" ); document.write( "9 pens = 3 dollars
\n" ); document.write( "12 pens = 4 dollars
\n" ); document.write( "And so on\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "The left side is triple that of the right side. \r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "In general we have
\n" ); document.write( "3y pens = y dollars
\n" ); document.write( "where y is some nonnegative real number
\n" ); document.write( "We'll further say
\n" ); document.write( "y = amount of money spent on pens\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Whatever dollar amount (y) you spent on pens, the number of pens you get is triple of that (3y)
\n" ); document.write( "So p = 3y where p is the number of pens\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "In the previous section, we found that $40 was spent on pens.
\n" ); document.write( "Use y = 40 to find p
\n" ); document.write( "p = 3y
\n" ); document.write( "p = 3*40
\n" ); document.write( "p = 120\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "So 120 pens were purchased.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "-----------------------------------------\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Earlier we defined p as the number of pens.
\n" ); document.write( "Let's make c and m the number of pencils and markers. \r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "In other words,
\n" ); document.write( "p = number of pens
\n" ); document.write( "c = number of pencils
\n" ); document.write( "m = number of markers
\n" ); document.write( "all of these values are nonnegative whole numbers\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "From fact 4, we know that,
\n" ); document.write( "c = (1/6)*p
\n" ); document.write( "c = p/6
\n" ); document.write( "c = 120/6 ... plug in p = 120
\n" ); document.write( "c = 20
\n" ); document.write( "Bob purchased 20 pencils\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "And from fact 5, we can say,
\n" ); document.write( "m = (2/5)*c
\n" ); document.write( "m = (2/5)*20 ... plug in c = 20
\n" ); document.write( "m = 0.4*20
\n" ); document.write( "m = 8
\n" ); document.write( "He also bought 8 markers\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "We have this summary
\n" ); document.write( "120 pens purchased
\n" ); document.write( "20 pencils purchased
\n" ); document.write( "8 markers purchased\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "This shows he bought 120+8 = 128 pens and markers\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "That wraps up the first question.\r
\n" ); document.write( "\n" ); document.write( "-----------------------------------------\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Now onto the second question.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Recall earlier that $100 was spent overall.
\n" ); document.write( "Let's bump this up to $175\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "The ratio 4x:5x:1x would then lead us to
\n" ); document.write( "4x+5x+1x = 175
\n" ); document.write( "10x = 175
\n" ); document.write( "x = 175/10
\n" ); document.write( "x = 17.5\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "This means
\n" ); document.write( "4x = 4*17.5 = 70
\n" ); document.write( "dollars is spent on pens\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Then y = 70 leads to
\n" ); document.write( "p = 3y
\n" ); document.write( "p = 3*70
\n" ); document.write( "p = 210
\n" ); document.write( "210 pens were purchased\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "And,
\n" ); document.write( "c = p/6
\n" ); document.write( "c = 210/6
\n" ); document.write( "c = 35
\n" ); document.write( "35 pencils were purchased\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "=================================================\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Final Summary:\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Question: How many pens and markers did he buy?
\n" ); document.write( "Answer: 128\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Question: How many pencils could he buy for 175 dollars?
\n" ); document.write( "Answer: 35
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