Ratio and Proportion, Indicies and logrithm Part-2

07) The third proportional between (a- b)²

        and (a+ b)^{2 is:}

       (a) (a+b)/ (a -b)

       (b) (a-b)/(a+b)

    (c)   (a- b)² /(a+b)

   (d) (a- b)³ /(a+b)

08) If p:q is the sub-duplicate ratio of 

        p- x² : q – x²  then x² is   :

        (a) p / (p+q)

        (b) q / (p+q)    

        (c) (qp) / (p-q)

        (d) None

09) 7 log(16/15) + 5 log(25/24) + 3 log (81/80)

       is equal to :

       (a) 0

       (b) 1    

       (c) log 2

       (d) log 3

10) If log₂[log₃(log₂ x)] = 1, then x equal :

       (a) 128

       (b) 256

       (c) 512

       (d) None

11) Two numbers are in the ratio 2:3 and the

        difference of their squares is 320. The 

        numbers are:

       (a) 12, 18

       (b) 16, 24

       (c) 14, 21

       (d) None

12) Ratio of earnings of A and B is 4:7.

        If the earnings of A increase by 50%

        and those of B decrease by 25%, the 

       new ratio of their earning becomes 8: 7

       what is A's earning?

      (a) Rs. 21000

      (b) Rs.26000

      (c) Rs.28000

      (d) Data inadequate.