# SOLUTION: Bob invested \$21,000, part at 18% and part at 8%. If the total interest at the end of the year is \$1,980, how much did he invest at 18%?

Algebra ->  -> SOLUTION: Bob invested \$21,000, part at 18% and part at 8%. If the total interest at the end of the year is \$1,980, how much did he invest at 18%?      Log On

 Ad: Mathway solves algebra homework problems with step-by-step help! Ad: Algebrator™ solves your algebra problems and provides step-by-step explanations!

 Click here to see ALL problems on Graphs Question 106663: Bob invested \$21,000, part at 18% and part at 8%. If the total interest at the end of the year is \$1,980, how much did he invest at 18%?Answer by elima(1433)   (Show Source): You can put this solution on YOUR website!Bob invested \$21,000, part at 18% and part at 8%. If the total interest at the end of the year is \$1,980, how much did he invest at 18%? x+y=21000 .18x+.08y=1980 ------------------------ x=21000-y .18(21000-y)+.08y=1980 3780-.18y+.08y=1980 -.1y=-1800 y=18000 ------------ x+18000=21000 x=3000 ------------------ so he invested \$3000 at 18% :)