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: 
Step-by-step explanation:
<h3>
The exercise is: " Evaluate 
when 
and 
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Given the following expression:
You can follow these steps in order to evaluate it:
1. Substitute and into the expression provided in the exercise:
2. Solve the multiplications. Remember that:
Then:
3. Reduce the fraction. Notice that the numerator 6 and the denomiantor 4 can be both divided by 2. Then:
4. Solve the addition:
Since the number 21 has a denominator 1, the Least Common Denominator is:
Then, the sum is:
Answer:
Step-by-step explanation:
x = number of rows
780=x(x+4)
there are 26 rows and 30 students in each row 26*30=780
The system of equations is
n + d = 27
n + 5d = 55
Step-by-step explanation:
The given is:
- Kiran has 27 nickels and quarters in his pocket
- They worth a total of $2.75
- We need to write a system of equations to represent the relationships between the number of nickels n, the number of quarters d, and the dollar amount in this situation
∵ The number of nickles is n
∵ The number of quarters is d
∵ There are 27 nickles and quarters
∴ n + d = 27 ⇒ (1)
∵ 1 nickel = 5 cents
∵ 1 quarter = 25 cents
- Multiply n by 5 and d by 25 to find their value
∴ They worth = 5n + 25d
∵ They worth a total of $2.75
- Chang the dollar to cent
∵ 1 dollar = 100 cents
∴ $2.75 = 2.75 × 100 = 275 cents
- Equate their value by 275
∴ 5n + 25d = 275
- Simplify it by divide each term by 5
∴ n + 5d = 55 ⇒ (2)
The system of equations is
n + d = 27
n + 5d = 55
Learn more:
You can learn more about the system of equations in brainly.com/question/2115716
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