All PSAT Math Resources
Example Questions
Example Question #1 : How To Find Inverse Variation
Find the inverse of .
To find the inverse we first switch the variables then solve for y.
Then we subtract from each side
Now we divide by to get our final answer. When we divide by we are left with . When we divide by we are left with . Thus resulting in:
Example Question #1 : How To Find Inverse Variation
Find the inverse equation of:
To solve for an inverse, we switch x and y and solve for y. Doing so yields:
Example Question #1 : How To Find Inverse Variation
Find the inverse equation of .
1. Switch the and variables in the above equation.
2. Solve for :
Example Question #2 : How To Find Inverse Variation
When , .
When , .
If varies inversely with , what is the value of when ?
If varies inversely with , .
1. Using any of the two combinations given, solve for :
Using :
2. Use your new equation and solve when :
Example Question #1 : How To Find Inverse Variation
x |
y |
If varies inversely with , what is the value of ?
An inverse variation is a function in the form: or , where is not equal to 0.
Substitute each in .
Therefore, the constant of variation, , must equal 24. If varies inversely as , must equal 24. Solve for .
Example Question #611 : Algebra
Evaluate the following equation when and round your answer to the nearest hundredth.
1. Plug in wherever there is an in the above equation.
2. Perform the above operations.
Example Question #1 : How To Evaluate A Fraction
Mary walked to school at an average speed of 2 miles per hour and jogged back along the same route at an average speed of 6 miles per hour. If her total traveling time was 1 hour, what was the total number of miles in the round trip?
Since Mary traveled 3 times as quickly coming from school as she did going to school (6 miles per hour compared to 2 miles per hour), we know that Mary spent only a third of the time coming from school as she did going. If x represents the number of hours it took to get to school, then x/3 represents the number of hours it took her to return.
Knowing that the total trip took 1 hour, we have:
x + x/3 = 1
3x/3 + 1x/3 = 1
4x/3 = 1
x = 3/4
So we know it took Mary 3/4 of an hour to travel to school (and the remaining 1/4 of an hour to get back).
Remembering that distance = rate * time, the distance Mary traveled on her way to school was (2 miles per hour) * (3/4 of an hour) = 3/2 miles. Furthermore, since she took the same route coming back, she must have traveled 3/2 of a mile to return as well.
Therefore, the the total number of miles in Mary's round trip is 3/2 miles + 3/2 miles = 6/2 miles = 3 miles.
Example Question #613 : Algebra
If then which of the following is equal to ?
To raise to the exponent , square and then take the cube root.
Example Question #614 : Algebra
Solve
infinitely many solutions
–1
no solution
0
infinitely many solutions
The common denominator of the left side is x(x–1). Multiplying the top and bottom of 1/x by (x–1) yields
Since this statement is true, there are infinitely many solutions.
Example Question #615 : Algebra
Evaluate when x=11. Round to the nearest tenth.
1.8
0.2
0.3
1.9
1.8
Wherever there is an x, plug in 11 and perform the given operations. The numerator will be equal to 83 and the denominator will be equal to 46. 83 divided by 46 is equal to 1.804… and since the second decimal place is not greater than or equal to 5, the first decimal place stays the same when rounding so the final answer is 1.8.