Answer:
90 g of water should be added and he will make 900 g of solution.
Step-by-step explanation:
Let x g be the amount of salt Ilya add to 810g of water to make 10% solution. Then 810+x g is the amount of new solution. Thus,
810+x - 100%,
x - 10%.
Mathematically,
So 90 g of water should be added and he will make 810+90=900 g of solution.
Answer:
Brand A = 21 heart-rate watches.
Brand B = 13 heart-rate watches.
Step-by-step explanation:
Let A be the number of Brand A heart watches and B be the number of Brand B heart watches.
We have been given that a nonprofit community health organization purchased 34 heart-rate watches for use at a wellness center.
We can represent this information in an equation as:
We have been given that in a certain year, brand A of heart-rate watch cost $39.99 and brand B cost $59.99 and the organization spent $1619.66 for the watches.
We can represent this information in an equation as:
We will use substitution method to solve our system of equations.
From equation (1) we will get,
Substituting in equation(2) we will get,
Therefore, the organisation purchased 13 heart-rate watches of brand B.
Now let us substitute B=13 in equation (1).
Therefore, the organisation purchased 21 heart-rate watches of brand A.