All SAT Math Resources
Example Questions
Example Question #31 : Algebra
If is defined for all numbers and to be , then what is ?
In evaluating, we can simply plug in 4 and 2 for and respectively. We then get .
Example Question #32 : Algebra
Internet service costs $0.50 per minute for the first ten minutes and is $0.20 a minute thereafter. What is the equation that represents the cost of internet in dollars when time is greater than 10 minutes?
The first ten minutes will cost $5. From there we need to apply a $0.20 per-minute charge for every minute after ten. This gives
.
Example Question #33 : Algebra
John goes on a trip of kilometers at a speed of kilometers an hour. How long did the trip take?
If we take the units and look at division, will yield hours as a unit. Therefore the answer is .
Example Question #34 : How To Find The Solution To An Equation
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 #1811 : Sat Mathematics
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 #1812 : Sat Mathematics
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.