Consecutive Percentage Increase and decrease

Consecutive percent increase and decrease:

1.       x percent of y percent of z is decreased by y percent. What is the result?

(A)  (100xyz - xy^2z) / 1,000,000 
(B)  (xz - y) / 100  
(C)  (xz - y) / 10,000
(D)  (xyz - 2y) / 100   

(E)  (xyz - 2y) / 10,000

2.                   Increasing the original price of article by 15 percent and then increasing the new price by 15 percent is equivalent to increasing the original price by

3.                   During a two week period, the price of an ounce of silver increased by 25 % by the end of the first week and then decreased by 20 percent of this new price by the end of the second week. If the price of silver was x dollars per ounce at the beginning of the two- week period , what was the price, in dollars per ounce , by the end of the period?

(A)  0.8x          (B) 0.95x          (C)  x      (D) 1.05 x      (E) 1.25 x

4.                   Lucy invested $10,000 in a new mutual fund account exactly three years ago the value of the account increased by 10 percent during the first year, increased by 5 percent during the second year, and decreased by 10 percent during the third year what is the value of the account today?

(A) $10,350           (B) $10,395        (C) $10,500        (D) $11,500          (E) $12,705

5.                   Column A:  50 as a percent of 30            Column B: the percent increase from 30 to 80

6. On a certain morning, stock X is worth $x ,where x is positive 

Column A:  the price of stock X if it decreases in value by 12%,then increase by 18%

Column B: the price of stock X if it decreases in value by 13%,then increase by 19%

7.  250% of x is increased by 250% to become 350 . what is value of x ?

8. If positive integer m is increased by 20% , decreased by 25% , and then increased by 60% , the resulting number is what percent of m?

9. An investment loses half its value in the morning, and then increase in value by 50% that afternoon; no other changes occur to the value of the investment (assume the investments original value was a positive number).

10. Column A:  The value of the investment before the days changes

       Column B: The value of the investment after the days changes

11. If a number is increased by 20% , decreased by 15% , and increased by 7%, the overall percent change is closest to  a

(A)  2%increase          (B) 2% decrease        (C) 9% increase      (D) 12% increase

(E) 14% increase

12.                                          In April, the price of fuel increased by 40%

                                                 In May, the price rose by another 30%

Column A:  The price increase in April                Column B: The price increase in May