If money is invested at r percent interest, compounded annually, the amount of the investment will double in approximately 60/r years. If Pat's parents invested $7,000 in a long-term bond that pays 6 percent interest, compounded annually, what will be the approximate total amount of the investment 20 years later, when Pat is ready for college?	Choices
A) $20000	B) $14000	C) $12000	D) $10000	E) $9000
Since investment doubles in 60/r years, then for r=6 it'll double in   60/6= 
<gadget id="calculator">  60/6</gadget>
<output>10</output>
~10 years (we are not asked about the exact amount so such an approximation will do). Thus after 20 years investment will become $7,000*2=$14,000 .   Answer: $14000
<result>B</result>
If money is invested at r percent interest, compounded annually, the amount of the investment will double in approximately 60/r years. If Pat's parents invested $7,000 in a long-term bond that pays 6 percent interest, compounded annually, what will be the approximate total amount of the investment 20 years later, when Pat is ready for college?