The rate of a certainchemical reaction is directly proportional to the square of the concentrationof chemical A present and inversely proportional to the concentration ofchemical B present. If the concentrationof chemical B is increased by 100 percent, which of the following is closest tothe percent change in the concentration of chemical A required to keep thereaction rate unchanged?

If ~$\left (5 ^{21} \right )\left ( 4^{11} \right )=2\left ( 10^{n} \right )$~, what is the value of n ?

If x and y are integers and3^(x - 4) = 3^(y + 2), what is y in terms of x ?

A set of 15 differentintegers has a median of 25 and a range of 25. What is the greatest possible integer that could be in this set?

The cost to park a car in acertain parking garage is $8.00 for up to 2 hours of parking and $1.75 for eachhour in excess of 2 hours. What is theaverage (arithmetic mean) cost per hour to park a car in the parking garage for9 hours?

If a equals the sum of theeven integers from 2 to 20, inclusive, and b equals the sum of the odd integersfrom 1 to 19, inclusive, what is the value of a - b ?

For each of her sales, asaleswoman receives a commission equal to 20 percent of the first $500 of thetotal amount of the sale, plus 30 percent of the total amount of the sale inexcess of $500. If the total amount ofone of her sales was $800, the saleswoman's commission was approximately whatpercent of the total amount of the sale?

A 4-person task force is tobe formed from the 4 men and 3 women who work in Company G's human resourcesdepartment. If there are to be 2 men and2 women on this task force, how many different task forces can be formed?

If d is the standarddeviation of x, y, and z, what is the standard deviation of x + 5, y + 5, and z+ 5 ?

Ifthe speed of x meters per second is equivalent to the speed of y kilometers perhour, what is y in terms of x ?

(1kilometer = 1,000 meters)