SAT Math › SAT Mathematics
Find the decimal equivalent to the percentage:
In order to find the decimal equivalent of a percentage, the number that makes up the percent has to be divided by 100. However, since it is division by a power of 10, we can accomplish the same thing, by moving the decimal point 2 places to the left, thus making the number smaller. For this problem, that looks like this:
Presented with a deck of fifty-two cards (no jokers), what is the probability of drawing either a face card or a spade?
A face card constitutes a Jack, Queen, or King, and there are twelve in a deck, so the probability of drawing a face card is .
There are thirteen spades in the deck, so the probability of drawing a spade is .
Keep in mind that there are also three cards that fit into both categories: the Jack, Queen, and King of Spades; the probability of drawing one is
Thus the probability of drawing a face card or a spade is:
Simplify:
Although we have different bases, we know that .
Therefore,
.
Finally, we factor out to get
.
What is the least common multiple of ?
Least common multiple is the smallest number that is divisible by two or more factors. Since are prime numbers and can't be broken down to smaller factors, we just multiply them to get
as our answer.
When multplying exponents, we need to make sure we have the same base.
Since we do, all we have to do is add the exponents.
The answer is .
An arithmetic sequence begins as follows:
Give the first integer in the sequence.
The sequence has no integers.
Rewrite all three fractions in terms of their least common denominator, which is :
;
remains as is;
The sequence begins
Subtract the first term from the second term
to get the common difference
:
Setting and
,
If this common difference is added a few more times, a pattern emerges:
...
All of the denominators end in 4 or 9, so none of them can be divisible by 20. Therefore, none of the terms will be integers.
What is the area of a square that has a diagonal whose endpoints in the coordinate plane are located at (-8, 6) and (2, -4)?
100
100√2
50√2
50
200√2
Simplify:
When adding exponents, you want to factor out to make solving the question easier.
We can factor out to get
.
Now we can add exponents and therefore our answer is
.
A regular seven sided polygon has a side length of 14”. What is the measurement of one of the interior angles of the polygon?
128.57 degrees
257.14 degrees
180 degrees
154.28 degrees
252 degrees
The formula for of interior angles based on a polygon with a number of side n is:
Each Interior Angle = (n-2)*180/n
= (7-2)*180/7 = 128.57 degrees
One line has four collinear points in order from left to right A, B, C, D. If AB = 10’, CD was twice as long as AB, and AC = 25’, how long is AD?
45'
40'
50'
35'
30'
AB = 10 ’
BC = AC – AB = 25’ – 10’ = 15’
CD = 2 * AB = 2 * 10’ = 20 ’
AD = AB + BC + CD = 10’ + 15’ + 20’ = 45’