SAT Math : How to find the part from the whole
Study concepts, example questions & explanations for SAT Math
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Example Questions
Example Question #1 : Whole And Part
If a TV show is 45 minutes long, what fraction of the show is completed 5 minutes after it begins?
1/4
1/9
1/3
1/10
1/2
1/9
5 minutes out of 45 have been completed. We can represent this as a fraction: 5/45. When simplified, this yields 1/9.
Example Question #2 : Whole And Part
A birthday cake is cut into 8 pieces. On the first night three pieces are eaten. On the second night, 20% of the remaining cake was eaten. On the third night, half of the remaining cake was eaten. How many slices were left to eat on the fourth night?
2
3
1/2
4.5
1
2
First night: 8 – 3 = 5 remaining.
Second night: 20% of 5 remaining = .2 * 5 = 1 slice Therefore 4 remaining.
Third night: ½ of the 4 remaining = ½*4 = 2 slices remaining
Example Question #1 : How To Find The Part From The Whole
There was a malfunction at a candy factory and the machines only put red, purple, and green candy into the bags. If 1/4 of the candies were red and 3/8 were green, how many purple candies were in the bag, if each bag can hold 16 pieces?
3
6
10
4
8
6
Since 1/4 of the 16 are red: 16 * 1/4 = 4 red candies. With 3/8 being green:
16 X 3/8 = 6 green candies. 16 – 4 – 6 = 6 candies remain, which must be purple.
Example Question #5 : Whole And Part
In the 30-day month of January, for every three days it snowed, there were seven days it did not snow. The number of days in January on which it did not snow was how much greater than the number of days in January on which it snowed?
13
10
12
14
11
12
The question tells us that for every ten-day period in January (a three-day period plus a seven-day period), it snowed on 3 of those days and did not snow on 7 of those days. Since January has 30 days, it has 3 ten-day periods, so we multiply the numbers given for the 10-day period by 3 to find the number of days with and without snow during the 30-day period. Doing this, we see that it snowed 3 * 3 = 9 days and did not snow 7 * 3 = 21 days during the 30-day period. Since the question asks how much greater the number of days on which it did not snow is than the number of days on which it snowed, we subtract as follows: number of days it did not snow - number of days it snowed = 21 – 9 = 12.
Example Question #5 : Whole And Part
Mikey has one full box of cereal. On Saturday, he eats 1/3 of the the box. On Sunday he eats 2/3 of what is left. How much of the box is still left?
2/9
4/9
2/3
5/9
none
2/9
If Mikey eats 1/3 of the box, he is left with 1 – 1/3 = 2/3.
When he eats 2/3 of what remains, he is eating 2/3 of 2/3, or 4/9 of the box.
2/3 – 4/9 = 2/9
Example Question #6 : Whole And Part
What is the remainder when 27 is divided by 6?
4.5
0.5
3
4
8
3
Long division is the fastest way: 6 goes into 27 four times. 6 times four is 24. 27 – 24 = 3.
Example Question #1 : How To Find The Part From The Whole
A pitcher is currently 
Let p represent the total capacity of the pitcher. The current volume in the pitcher is 
Solve this equation for 
Remember, 
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