if money is invested at r percent interest , compounded annually , the amount of the investment will double in approximately 50 / r years . if luke ' s parents invested $ 15500 in a long term bond that pays 12 percent interest compounded annually , what will be the approximate total amount of the investment 12 years later , when luke is ready for college ?
answer equals e in 48 years . i thought by 50 th year it would reach 120,000 . options should have been separated more widely for clarity .
add(subtract(multiply(12, 12), 50), const_1)