Answer:
The total time that Jim needs to change x oil changes and y tire changes is less than 180 min.
The time needed for x oil changes is 12 * x.
The time needed for y tire changes is 18 * y.
The total time is the sum of the above times and needs to be less than 180 that is
12 * x + 18 * y < 180 divide both sides of equation by 6
12/6 * x + 18/6*y < 180/6
2*x + 3*y < 30
2*x < 30 - 3*y divide both sides by 2 to get the inequality for x
x < 30/2 - 3/2*y = 15 - 1.5 y < 15 that is x < = 15
2*x + 3*y < 30
3*y < 30 - 2*x divide both sides by 3 to get the inequality for y
y < 30/3 - 2/3 *x = 10 - 2/3*x < 10 that is y < = 10
Also we can write x + y < x+ 3/2 * y < 15.
Explanation:
Jim's can do not more then 5 oil changes and not more then 10 tire changes or all together she can do not more then 15 total of oil and tire changes.
Answer: (2) decreasing the concentration of HCl(aq) to 0.1 M
Explanation: Rate of a reaction depends on following factors:
1. Size of the solute particles: If the reactant molecules are present in smaller size, surface of particles and decreasing the size increases the surface area of the solute particles. Hence, increasing the rate of a reaction.
2. Reactant concentration: The rate of the reaction is directly proportional to the concentration of reactants.
3. Temperature: Increasing the temperature increases the energy of the molecules and thus more molecules can react to give products and rate increases.
(1) Increasing the initial temperature to 25°C will increase the reaction rate.
(2) Decreasing the concentration of HCl(aq) to 0.1 M will decrease the reaction rate due to lesser concentration.
(3) Using 1.2 g of powdered Mg will increase the reaction rate due to large surface area.
(4) Using 2.4 g of Mg ribbon will increase the reaction rate due to high concentration of reactants.
