For a chemistry experiment Laura needs 300 ml of a 15% sulphuric acid solution. The Science Department has quantities of 5% acid solution and 20% acid solution. What volume of each solution is required to mix together to get her required concentration? Use a complete algebraic solution, including a proper verification.

100 ml of 5% solution

200 ml of  20% solution

Step-by-step explanation:

x = amount of 5% solution

y = amount of 20% solution

System of equations:

x + y = 300

.05x + .20y = 300(.15)

Solve by substitution:  let y = 300 - x

.05x + .2(300-x) = 300(.15)

.05x + 60 - .20x = 45

-.15x = -15

x = 100, therefore y = 200

c. y = 1/4 x + 5

step-by-step explanation:

first, put the equation of the line on the graph into slope-intercept form

(y = mx + b):   y = -4x + 8

second, a perpendicular line has to have "an opposite/reciprocal slope" to the original slope. so, find the "m" value in your original equation (it's -4, right? )

original slope: m = -4   perpendicular slope: change the sign to its opposite and find the reciprocal ("flip" the number)

new slope is now positive (b/c the original slope was negative 4), and it's 1/4 (not the original slope of 4 or 4/1)