Clara invests $5,000 in an account that pays 6.25% interest per year. after how many years will her investment be worth $10,000?

 I think the interest is compounded yearly, if so 
A = $10000 
P = $5000 
r = 6.25% = 0.0625 
A = P (1+r/100)^t where t denotes time in years 
10000 = 5000 (1+0.0625)^t 
10000/5000 = 1.0625^t 
2 = 1.0625^t 
Use logarithms or a scientific calculator 
t = 11.5 
In 11.5 years $5000 investment be worth of $10000 
>>>>>>>>>>>>> 
In case the interest is simple interest 
Interest = Amount - Principal = $10000-$5000 = $5000 
Time = 100*Interest / (Principal*Rate 
= 100*5000 / (5000*6.25) 
= 16 years 
In 16 years $5000 investment be worth of $10000
Hope this was helpful! (: If so, please give brainliest (;