Solve. 18) HOw many liters of water must be evaporated from 10 L of a40% salt so
ID: 3094837 • Letter: S
Question
Solve.18) HOw many liters of water must be evaporated from 10 L of a40% salt solution to produce a 50% solution?
21) A securities broker advised a client to invest a total of$21,000 in bonds paying 12% interest and in certificates of depositpaying 5 1/4% interest. The annual income from these investmentswas $2250. Find out how much was invested at each rate.
Thank you! Sorry for having 2 problems, but I really need thehelp.
18) HOw many liters of water must be evaporated from 10 L of a40% salt solution to produce a 50% solution?
21) A securities broker advised a client to invest a total of$21,000 in bonds paying 12% interest and in certificates of depositpaying 5 1/4% interest. The annual income from these investmentswas $2250. Find out how much was invested at each rate.
Thank you! Sorry for having 2 problems, but I really need thehelp.
Explanation / Answer
18) HOw many liters of water must be evaporated from 10 L of a40% salt solution to produce a 50% solution?ounces liquid %salt total salt
40% 10 .4 .40(10)=4
50% 10-x .5 .5(10-x)=5-.5x
4=5-.5x
subtract 5 both sides
-1=-.5x
divide both sides by -.5
.5=x
1/2 liter water
21) A securities broker advised a client to invest a total of$21,000 in bonds paying 12% interest and in certificates of depositpaying 5 1/4% interest. The annual income from these investmentswas $2250. Find out how much was invested at each rate.
x = amount invested in bonds
.12 = interest bonds getting
.12x = interest bonds received
21000-x=amount invested in cd's
5.25=.0525=interest cd's get
.0525(21000-x)=interest cd's get
.0525(21000-x)+.12x=2250
multiply
1102.5-.0525x+.12x=2250
combine like terms
1102.5+.0675x=2250
subtract 1102.5 from each side
.0675x=1147.5
divide both sides by .0675
x=17000 bonds
21000-17000=4000 in cd's