When the concentration of a solution is expressed in weight percentages, that is just equal to the mass of solute over the mass of the total solution. For a solution weighing 210 grams, 5% of it is salt. That is equal to
210*0.05= 10.5 g salt
The rest of the amount, determined by difference, is the amount of solvent which is water.
water = 210-10.5 = 199.5 g salt
To solve for the new concentration, you add up 15 g to the already existing 10.5 g of salt in the solution. The water, on the other hand, remains constant.
Concentration = (15+10.5)/(210+15) = 0.1133 or 11.33%
Answer:
3.64 Km.
Step-by-step explanation:
Given,
Total population = 20,000 people
Population density = 480 people per square kilometer
Area of the circle town
Radius of the circle town
Hence, the radius of circle town is equal to 3.64 Km.
Answer:
£56
Step-by-step explanation:
you first have to find out how much one kg is so you do 42/3=14
then times is by 4, 14x4=56
The original price was 65
<span>If Mary earns 7$ an hour, we need to multiplicate 7$ by the number of hours worked for the entire week so we can get the salary per week. And when we want to know how many hours she had worked, we have to "transform" the equation :
Salary per week = salary per hours x worked hours
Here, we know to informations : salary per hours and salary per week.
Worked hours = salary per week / salary per day
Worked hours = 143.50 / 7
Worked hours = 20.5
The greatest number of hours thats he works is 20h30.</span>
