Two solutions of salt water contain 0.07% and 0.23% salt respectively. a lab technician wants to make 1 liter of solution which contains 0.11% salt. how much of each solution should she use?

0.75 liter of 0.07 % is used and 0.25 liter of 0.23 % salt is used

Solution:

We have to 1 liter of final solution

Let "x" be the salt solution of 0.07 %

Then, (1 - x) is the salt solution of 0.23 %

Then final solution should be 1 liter of solution which contains 0.11 % salt

Thus, 0.07 % of "x" is mixed with 0.23 % of (1 - x) to make a solution 0.11 % of 1 liter

Thus a equation is framed as:

0.07 % of x + 0.23 % of (1 - x) = 0.11 % of 1

Thus 0.75 liter of 0.07 % is used

And,

1 - x = 1 - 0.75 = 0.25

Thus 0.25 liter of 0.23 % salt is used

let x be the money she spent so that she can earn the free t-shirt.

since, she already spent $112.49

⇒

also, as per the statement: jennifer must spend $250 or more in order to qualify for a free t-shirt at the store.

then,

we have an inequality i.,e

subtract 112.49 from both sides we get;

therefore, $137. 51 more money does jennifer need to spend so that she can earn the free t-shirt