document.write( "Question 193333: Please check my work and let me know if I have the right answers, thank you.
\n" ); document.write( "Applications of Linear Equations
\n" ); document.write( "1. Joe has a collection of nickels and dimes that is worth $6.05. If the number of dimes was doubled and the number of nickels was decreased by 10, the value of the coins would be $9.85. How many dimes does he have?\r
\n" ); document.write( "\n" ); document.write( "43 dimes\r
\n" ); document.write( "\n" ); document.write( "x * $0.1 + y * $0.05 = $6.05\r
\n" ); document.write( "\n" ); document.write( "x * 2 * $0.1 + (y - 10) * $0.05 = $9.85\r
\n" ); document.write( "\n" ); document.write( "Solve for x in equation 1\r
\n" ); document.write( "\n" ); document.write( "x * $0.1 = $6.05 - y * $0.05\r
\n" ); document.write( "\n" ); document.write( "x = $60.5 - $0.5y\r
\n" ); document.write( "\n" ); document.write( "Plug into equation 2\r
\n" ); document.write( "\n" ); document.write( "($60.5 - $0.5y) * 2 * $0.1 + (y - 10) * $0.05 = $9.85\r
\n" ); document.write( "\n" ); document.write( "$12.1 - $0.1y + $0.05y - $0.5 = $9.85\r
\n" ); document.write( "\n" ); document.write( "$1.75 = $0.05y\r
\n" ); document.write( "\n" ); document.write( "y = 35 nickels\r
\n" ); document.write( "\n" ); document.write( "x * $0.1 + 35 * $0.05 = $6.05\r
\n" ); document.write( "\n" ); document.write( "$0.1x = $4.30\r
\n" ); document.write( "\n" ); document.write( "x = 43 dimes\r
\n" ); document.write( "\n" ); document.write( "Confirm result, does\r
\n" ); document.write( "\n" ); document.write( "43 * 2 * $0.1 + (35 - 10) * $0.05 = $9.85\r
\n" ); document.write( "\n" ); document.write( "$9.85 = $9.85\r
\n" ); document.write( "\n" ); document.write( "Yes\r
\n" ); document.write( "\n" ); document.write( "2. An express train and a local train both leave Gray’s Lake at 12:00 noon and head for Chicago 60 miles away. The express travels twice as fast as the local and arrives 2 hours ahead of it. Find the speed of each train. \r
\n" ); document.write( "\n" ); document.write( "v1 = speed of express train
\n" ); document.write( "v2 = speed of local train\r
\n" ); document.write( "\n" ); document.write( "v1 = 30 MPH
\n" ); document.write( "V2 = 15 MPH\r
\n" ); document.write( "\n" ); document.write( "v = d/t (velocity = distance / time)\r
\n" ); document.write( "\n" ); document.write( "t = d/v\r
\n" ); document.write( "\n" ); document.write( "t1 = 60 miles / 30 MPH\r
\n" ); document.write( "\n" ); document.write( "t1 = 2 hours\r
\n" ); document.write( "\n" ); document.write( "t2 = 60 miles / 15 MPH\r
\n" ); document.write( "\n" ); document.write( "t2 = 4 hours\r
\n" ); document.write( "\n" ); document.write( "Does, t1 = t2 - 2\r
\n" ); document.write( "\n" ); document.write( "2 hours = 2 hours\r
\n" ); document.write( "\n" ); document.write( "Yes\r
\n" ); document.write( "\n" ); document.write( "3. Walt made an extra $12,000 last year from a part-time job. He invested part of the money at 7% and the rest at 9%. He made a total of $970 in interest. How much was invested at 7%?
\n" ); document.write( "$5500 invested at 7%\r
\n" ); document.write( "\n" ); document.write( "x + y = $12,000
\n" ); document.write( "x * 0.07 + y * 0.09 = $970\r
\n" ); document.write( "\n" ); document.write( "x = $12,000 - y\r
\n" ); document.write( "\n" ); document.write( "($12,000 - y) * 0.07 + y * 0.09 = $970\r
\n" ); document.write( "\n" ); document.write( "$840 - 0.07y + 0.09y = $970\r
\n" ); document.write( "\n" ); document.write( "0.02y = $130\r
\n" ); document.write( "\n" ); document.write( "y = $6500 @ 9%, which means x = $5500 @ 7%\r
\n" ); document.write( "\n" ); document.write( "Double check, does\r
\n" ); document.write( "\n" ); document.write( "$5500 * 0.07 + $6500 * 0.09 = $970\r
\n" ); document.write( "\n" ); document.write( "$970 = $970\r
\n" ); document.write( "\n" ); document.write( "Yes
\n" ); document.write( "

Algebra.Com's Answer #145151 by solver91311(24713)\"\" \"About 
You can put this solution on YOUR website!
\r
\n" ); document.write( "\n" ); document.write( "#1 and #3 are done correctly. You have the correct answers for #2, but you really don't show how you got them.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Express train:\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Local train:\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "and\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Since the distances are the same:\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "John
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" );