Third year. What was the amount of the dollar decrease in the property price during the second year

@gmat_group 
 
@AlijonovSirojiddin 
20.
 
 
The rate of a certain chemical reaction is directly proportional to 
the square of the concentration of chemical A present and 
inversely proportional to the concentration of chemical B present. 
If the concentration of chemical B is increased by 100 percent, 
which of the following is closest to the percent change in the 
concentration of chemical A required to keep the reaction rate 
unchanged? 
A) increase, 30% 
B) increase, 40% 
C) increase, 50% 
D) decrease, 40% 
E) decrease, 30% 

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@gmat_group 
 
@AlijonovSirojiddin 
21.
 
 
Of the 800 employees in a certain company, 70% have serviced 
more than 10 years. A number of y of those who have serviced 
more than 10 years will retire and no fresh employees join in. 
When is y if the 10 years employees become 60% of the total 
employees? 
A) 200 
B) 160 
C) 112 
D) 80 
E) 56 

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@gmat_group 
 
@AlijonovSirojiddin 
22.
 
 
Before being simplified, the instructions for computing income tax 
in Country R were to add 2 percent of one's annual income to the 
average (arithmetic mean) of 100 units of Country R's currency 
and 1 percent of one's annual income. Which of the following 
represents the simplified formula for computing the income tax, in 
Country R's currency, for a person in that country whose annual 
income is A? 
A) 50+A/200
B) 50+3A/100
C) 50+A/40
D) 100+A/50
E) 100+3A/100 

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