document.write( "Question 1101491: Ladt year, Tammy had $30,000 to invest. She invested some of it in an account that paud 7% simple interest per year, and she invested the rest in an account that paid 8% simple interest per year. After 1 year she recueved a total of $2280 in interest. How much did she invest in each account? \r
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Algebra.Com's Answer #716088 by richwmiller(17219)\"\" \"About 
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Total amount of money invested: $30000
\n" ); document.write( "x+y=30000,
\n" ); document.write( "Total yearly interest for the two accounts is: $2280
\n" ); document.write( "0.07*x+0.08*y=2280
\n" ); document.write( "x=30000-y
\n" ); document.write( "Substitute for x
\n" ); document.write( "0.07*(30000-y)+0.08*y=2280
\n" ); document.write( "Multiply out
\n" ); document.write( "2100-0.07*y+0.08*y=2280
\n" ); document.write( "Combine like terms.
\n" ); document.write( "0.01*y=180
\n" ); document.write( "Isolate y
\n" ); document.write( "y=$18,000.00 at 8% earns $1,440 interest
\n" ); document.write( "x=30000-y
\n" ); document.write( "Calculate x
\n" ); document.write( "x=$12,000.00 at 7% earns $840 interest
\n" ); document.write( "Check
\n" ); document.write( "0.07*12000+0.08*18000=2280
\n" ); document.write( "840+1440=2280
\n" ); document.write( "2280=2280
\n" ); document.write( "If 2280=2280 is TRUE and neither x nor y is negative then all is well
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