Question

2,3 answer its urgent

Answer 1

2)  simple interest:   I = P r t/100 = P * r/100 * (8 1/3) = P r /12
        sum = P + P r t = P [ 1 + r/12 ]  =  2 * P  given
         so   r / 12 = 1     =>  r = 12 %

   compound interest:  sum = P (1 + r/100)^t = 2 P   given
          (1 + r/100)^(25/3) = 2
           25/3 *  Log (1+ r/100) = Log 2
           Log (1 + r/100) = 3/25  * Log 2 = 0.0361
            1 + r/100 = 1.08673
           r = 100 *  0.08673 = 8.673%  

3)    5% of $ 9, 000    =   5 /100 *   9000  = 450 $