All PSAT Math Resources
Example Questions
Example Question #1809 : Sat Mathematics
With a head wind a plane can fly a certain distance in five hours. The return flight takes an hour less. How fast was the plane flying?
In general, .
The distance is the same going and coming; however, the head wind affects the rate. The equation thus becomes .
Solving for gives
.
Example Question #211 : 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 : Algebra
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 #212 : Algebra
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 #141 : Gre Quantitative Reasoning
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 #35 : Algebra
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 #142 : Gre Quantitative Reasoning
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 #326 : Algebra
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 #101 : Equations / Inequalities
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.
Certified Tutor
Certified Tutor
All PSAT Math Resources
