All SAT Math Resources
Example Questions
Example Question #41 : How To Find The Solution To An Equation
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 #213 : Algebra
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 #71 : How To Find The Solution To An Equation
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 #1812 : 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.
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.
Example Question #222 : Algebra
How much pure water must be added to 2 gallons of 90% pure cleaning solution to yield a 30% pure cleaning solution?
Let pure water be 0% and pure solution be 100%.
So the general equation to solve is:
where is the volume and the is percent solution.
So the equation to solve becomes
Solving shows that we need to add 4 gallons of pure water to 2 gallons of 90% pure cleaning solution to get a 30% pure solution.
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