During the process of diluting a solution to a lower concentration,

The amount of solute does not change.

Explanation:

Dilution :It is a process of making liquid more dilute .

In this process , the concentration of solute decreases in solution by adding more solvent . When we are adding more solvent such water into the solution, the concentration of solute decreases in solution.The solution is more dilute than before.But the amount of solute does not change,only  amount of solvent changes.The solution consist of solute and solvent.When amount of solvent change then the amount of solution is also changes.The concentration of solution is decreases.The volume of solution is also changes.

1. (1.2kw)x(15/60hours) = .3kwh --> a

2. (5kw)x(90/60hours)x(8cents/kwh) = $0.60 --> d

3. microwave --> 1200 watts = (1.2kw)x(6/60hours) = .12kwh

coffee-maker --> 900 watts = (.9kw)x(10/60hours) = .15kwh

therefore, it requires more energy for the coffee-maker to do the same amount of work.

so the answer is a.

the correct answer would be 6 feet.