document.write( "Question 123892: Mrs Lee bought 40 fun fair coupons. Some of the coupons were worth $2 and the rest were worth $5. The total value of all the coupons was $146. How many $5 coupons did Mrs Lee buy? \n" ); document.write( "
Algebra.Com's Answer #90893 by bucky(2189)\"\" \"About 
You can put this solution on YOUR website!
Let T represent the number of $2 coupons and F represent the number of $5 coupons.
\n" ); document.write( ".
\n" ); document.write( "The problem tells you that a total of 40 coupons were purchased. Therefore, we can write an equation
\n" ); document.write( "about the total number of coupons. The numbers of each type of coupon must total 40. In equation
\n" ); document.write( "form this is:
\n" ); document.write( ".
\n" ); document.write( "T + F = 40
\n" ); document.write( ".
\n" ); document.write( "The number of dollars spent on $2 coupons is the $2 multiplied by the number of $2 coupons purchased.
\n" ); document.write( "Since the number of $2 coupons purchased is the unknown T, the total dollar value of the $2
\n" ); document.write( "coupons is $2 times T or simply 2T. Similarly, the amount spent of $5 coupons is $5 times the
\n" ); document.write( "number of $5 coupons purchased or $5 times F or simply 5F. The total spent is $146, so we can
\n" ); document.write( "write the equation totaling the amounts spent for each type of coupon as:
\n" ); document.write( ".
\n" ); document.write( "2T + 5F = 146
\n" ); document.write( ".
\n" ); document.write( "Returning to the first equation for the total number of coupons sold we can subtract
\n" ); document.write( "F from both sides of the equation to find that:
\n" ); document.write( ".
\n" ); document.write( "T = 40 - F
\n" ); document.write( ".
\n" ); document.write( "So we can substitute 40 - F for its equivalent value T. Making this substitution into the dollar
\n" ); document.write( "equation we get:
\n" ); document.write( ".
\n" ); document.write( "2(40 - F) + 5F = 146
\n" ); document.write( ".
\n" ); document.write( "Doing the distributed multiplication on the left side results in:
\n" ); document.write( ".
\n" ); document.write( "80 - 2F + 5F = 146
\n" ); document.write( ".
\n" ); document.write( "The two terms containing F (the terms are -2F and + 5F) combine to give 3F, which reduces the
\n" ); document.write( "equation to:
\n" ); document.write( ".
\n" ); document.write( "80 + 3F = 146
\n" ); document.write( ".
\n" ); document.write( "Get rid of the 80 on the left side by subtracting 80 from both sides. This further reduces
\n" ); document.write( "the equation to:
\n" ); document.write( ".
\n" ); document.write( "3F = 66
\n" ); document.write( ".
\n" ); document.write( "Solve for F by dividing both sides of this equation by 3 to get:
\n" ); document.write( ".
\n" ); document.write( "F = 22
\n" ); document.write( ".
\n" ); document.write( "This tells you that 22 five dollar coupons were purchased.
\n" ); document.write( ".
\n" ); document.write( "Since a total of 40 coupons were bought, this means that the number of $2 coupons was
\n" ); document.write( "40 - 22 or 18.
\n" ); document.write( ".
\n" ); document.write( "Let's check the money spent. If 22 coupons were purchased at $5 each, a total of $110 was spent
\n" ); document.write( "(from $5 times 22).
\n" ); document.write( ".
\n" ); document.write( "And if 18 coupons were purchased at $2 each, a total of $36 was spent for these coupons.
\n" ); document.write( ".
\n" ); document.write( "This means that the total amount spent on coupons was $110 + $36 and that does total to $146
\n" ); document.write( "just as it should.
\n" ); document.write( ".
\n" ); document.write( "Hope this helps you to understand the problem.
\n" ); document.write( ".
\n" ); document.write( "
\n" );