All ACT Math Resources
Example Questions
Example Question #32 : Algebra
How much water should be added to of 90% cleaning solution to yield 50% cleaning solution?
Pure water is 0% and pure solution 100%. Let = water to be added.
in general where is the volume and is the percent.
So the equation to solve becomes
and
Example Question #31 : Linear / Rational / Variable Equations
Solve and
This problem is a good example of the substitution method of solving a system of equations. We start by rewritting the first equation in terms of to get and then substutite the into the second equation to get
.
Solving this equation gives and substituting this value into one of the original equations gives , thus the correct answer is .
Example Question #43 : Linear / Rational / Variable Equations
Joy bought some art supplies. She bought colored pencils for $1.25 per box and sketch pads for $2.25 each. Joy bought one more sketch pad than colored pencil boxes and spent $9.25. How many sketch pads did she buy?
Let = # of color pencil boxes and = # of sketch pads purchased.
So the equation to solve becomes .
Solving this equations leads to 2 colored pencil boxes and 3 sketch pads.
Example Question #36 : How To Find The Solution To An Equation
This question deals with absolute value equations which will normally gives you two solutions.
You need to solve two sets of equations for absolute value problems:
and
Example Question #141 : Algebra
Steve sells cars. His monthly salary is $1,000. He gets a $500 commission for each car he sells. If Steve wants to make $7,500 this month, how many cars would he have to sell?
Let = money earned and = number of cars sold
So
and solving shows that he needs to sell 13 cars to make $7,500.
Example Question #1813 : Sat Mathematics
A chemistry student needs to dilute some acid. How much pure water should be added to 2 gallons of 80% acid solution to yield 20% acid solution?
Let pure water = 0 % and pure acid = 100%
The general equation to use is:
where is the volume and is the percent solution.
So the equation to solve becomes and gallons of pure water needs to be added to get a 20% acid solution.
Example Question #41 : How To Find The Solution To An Equation
The Widget Company makes widgets. The monthly fixed costs are $750. It costs $45 to make each widget. The widgets sell for $75 a piece.
What is the monthly break-even point?
The break-even point is where the costs equal revenue.
Let = # of widgets sold.
Costs:
Revenue:
So the equation to solve becomes
So the break-even point occurs when they sell 25 widgets.
Example Question #41 : Equations / Inequalities
The Widget Company makes widgets. The monthly fixed costs are $750. It costs $45 to make each widget. The widgets sells for $75 a piece.
The Widget Company wants to make a profit of $3,000. How many widgets must be sold?
Profits = Revenues - Costs
Revenue:
Costs:
Profit:
So the equation to solve becomes
So a $3,000 profit occurs when they sell 125 widgets
Example Question #41 : How To Find The Solution To An Equation
Sally sells custom picture frames. Her monthly fixed costs are $350. It costs $10 to make each frame. Sally sells her picture frames for $35 each.
How many picture frames must Sally sell in order to break even?
The break-even point is where the costs equal the revenues.
Let = # of frames sold
Costs:
Revenues:
Thus,
So 14 picture frames must be sold each month to break-even.
Example Question #143 : Algebra
Sally sells custom picture frames. Her monthly fixed costs are $350. It costs $10 to make each frame. Sally sells her picture frames for $35 each.
To make a profit of $500, how many frames need to be sold?
Let = # of frames sold
Revenues:
Costs:
Profits =
So the equation to solve becomes
So 34 picture frames must be sold to make a $500 profit.