All PSAT Math Resources
Example Questions
Example Question #11 : How To Add Exponents
If , what is the value of ?
Using exponents, 27 is equal to 33. So, the equation can be rewritten:
34x + 6 = (33)2x
34x + 6 = 36x
When both side of an equation have the same base, the exponents must be equal. Thus:
4x + 6 = 6x
6 = 2x
x = 3
Example Question #81 : Exponents
What is the value of such that ?
We can solve by converting all terms to a base of two. 4, 16, and 32 can all be expressed in terms of 2 to a standard exponent value.
We can rewrite the original equation in these terms.
Simplify exponents.
Finally, combine terms.
From this equation, we can see that .
Example Question #11 : Exponents
How many of the following base ten numbers have a base five representation of exactly four digits?
(A)
(B)
(C)
(D)
None
Two
Four
Three
One
Three
A number in base five has powers of five as its place values; starting at the right, they are
The lowest base five number with four digits would be
in base ten.
The lowest base five number with five digits would be
in base ten.
Therefore, a number that is expressed as a four-digit number in base five must fall in the range
Three of the four numbers - all except 100 - fall in this range.
Example Question #11 : How To Add Exponents
Solve for :
Combining the powers, we get .
From here we can use logarithms, or simply guess and check to get .
Example Question #1111 : Psat Mathematics
If and are positive integers, and , then what is in terms of ?
is equal to which is equal to . If we compare this to the original equation we get