A chemist is mixing two solutions, solution A and solution B. Solution A is 15% water and solution Bis 20% water. She already has a beaker with 10mL of solution A in it. How many mL of solution B must be added to the beaker in order to create a mixture that is 18%
water?

15 ml

Step-by-step explanation:

We are told

Solution A = 15% of water

Solution B = 20% of water

Let's assume, the entire solution = 100ml

We are told that in the beaker we have 10 ml of Solution A already

Mathematically,

100 ml = 15%

10 ml = X

100ml × X = 15 × 10

X = 150/ 100

X = 1.5%

Hence in the beaker, we have 1.5% of water from Solution A

We are asked to find how many ml of solution B must be added to make the solution have 18% of water

Let y = number of ml of solution B

Hence

10 ml × 15%(0.15) = 1.5 ml of water - Equation 1

y ml × 20%( 0.20) = 0.20y ml of water Equation 2

Add up the above equation

10ml + y ml ×18% (0.18) = 1.5 + 0.20y

(10 + y)(0.18) = 1.5 + 0.20y

1.8 + 0.18y = 1.5 + 0.20y

Collect like terms

1.8 - 1.5  = 0.20y - 0.18y

0.3 = 0.02y

y = 0.3/0.02

y = 15ml                              

Therefore,15mL of solution B must be added to the beaker in order to create a mixture that is 18% water

step-by-step explanation:

descending order means to order the polynomials from the term with the largest exponent to the term with the smallest exponent.  

therefore, the correct answer is d.  

they are simplified

step-by-step explanation: