document.write( "Question 113120: Helen's age next year will be three times Dan's age last year. Their present ages total 32. How old is each now? \n" ); document.write( "
Algebra.Com's Answer #82358 by solver91311(24713)\"\" \"About 
You can put this solution on YOUR website!
This year Helen is h years old, and Dan is d years old. Helen's age next year then must be h + 1. And Dan's age last year must have been d - 1. The problem tells us:\r
\n" ); document.write( "\n" ); document.write( "Helen's age next year (h + 1) will be (=) 3 times Dan's age last year 3(d - 1).\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "So we can write:
\n" ); document.write( "Eq. 1) \"h%2B1=3%28d-1%29\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "We also know that their present ages, h and d, total 32, so we can write:
\n" ); document.write( "Eq. 2)\"h%2Bd=32\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Start by solving Eq. 2) for one of the variables (doesn't matter which, I'll choose to solve for h)
\n" ); document.write( "\"h=32-d\", Adding -d to both sides.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Now we have an expression that represents h in terms of d that can be substituted into Eq. 1), thus:
\n" ); document.write( "\"%2832-d%29%2B1=3%28d-1%29\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Now, simplify and solve for d:
\n" ); document.write( "\"33-d=3d-3\" Distributive and Associative Properties
\n" ); document.write( "\"-d-3d=-3-33\" Adding -3d and -33 to both sides
\n" ); document.write( "\"-4d=-36\" Collecting terms
\n" ); document.write( "\"d=-36%2F-4=9\" Divide both sides by -4, and now we know that this year, Dan is 9. Since the sum of their ages is 32, Helen must be 32 - 9 = 23.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Let's check the answer.\r
\n" ); document.write( "\n" ); document.write( "Helen's age next year will be 24. Dan's age last year was 8. 3 times 8 is 24. Furthermore, 9 + 23 = 32. So our numbers satisfy both of the conditions of the problem. Answer checks.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Hope that helps,
\n" ); document.write( "John\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "
\n" ); document.write( "
\n" );