Fractions
Help Questions
ACT Math › Fractions
What common number can you add to the numerator and denominator of to get
?
Explanation
Set up an equation where you add the same unknown number (x) to both the numerator and the denominator of the original fraction, and set the equation equal to .
Cross-multiply the fractions to simplify.
Now, solve for x.
The largest of three numbers is six less than four times the smallest number. The middle number is three more than twice the smallest number. The sum of twice the largest number, three more than three times the middle number, and four times the smallest number is 90. What is the value of the largest number?
14
10
12
18
22
Explanation
Because all the numbers are expressed in terms of the smallest number, let that number be represented by x. Therefore, the largest number can be expressed as 4x-6, and the middle number can be expressed as 2x+3. Plug those numbers into the addition equation and solve for x. Then plug the value for x into the expression representing the largest number.
2(4x-6) + (3+3(2x+3)) + 4(x) = 90 --> 18x = 90 --> x = 5
4(6)-6 = 14
How many rational numbers are between 1 and 2?
Just one
Two: 1 and 2
None
Infinitely many
Explanation
The definition of a rational number is an integer or a fraction. We can take the fractions 3/2, 4/3, 5/4, 6/5, 7/6, 8/7,...and continue in this way to realize there are infinitely many rational numbers.
Maria owns an art studio and spent in supplies. She sells her paintings for
each. How many paintings does Maria need to sell until she makes a profit?
Explanation
Divide the total money spent by the cost of each painting.
Therefore, to make a profit, she needs to sell more than this amount. Since she can't sell a portion of a painting, the answer has to be the next nearest whole number ().
A new car can travel an average of 63 miles per gallon of gasoline. Gasoline costs \$5.05 per gallon. How much would it cost to travel 6,363 miles in this car?
\$505
\$101
\$405.05
\$510
\$510.05
Explanation
First, find the total amount of gas necessary for the trip. 6363/63 = 101 gallons (easy to see as 63 * 100 = 6300 + 1 * 63 = 6363). Then multiply the number of gallons by the price per gallon of gasoline, 5.05 * 101 = \$510.05 and is your answer (again, easy to see when 5.05 * 100 + 1 * 5.05).
The largest of three numbers is six less than four times the smallest number. The middle number is three more than twice the smallest number. The sum of twice the largest number, three more than three times the middle number, and four times the smallest number is 90. What is the value of the largest number?
14
10
12
18
22
Explanation
Because all the numbers are expressed in terms of the smallest number, let that number be represented by x. Therefore, the largest number can be expressed as 4x-6, and the middle number can be expressed as 2x+3. Plug those numbers into the addition equation and solve for x. Then plug the value for x into the expression representing the largest number.
2(4x-6) + (3+3(2x+3)) + 4(x) = 90 --> 18x = 90 --> x = 5
4(6)-6 = 14
The largest of three numbers is six less than four times the smallest number. The middle number is three more than twice the smallest number. The sum of twice the largest number, three more than three times the middle number, and four times the smallest number is 90. What is the value of the largest number?
14
10
12
18
22
Explanation
Because all the numbers are expressed in terms of the smallest number, let that number be represented by x. Therefore, the largest number can be expressed as 4x-6, and the middle number can be expressed as 2x+3. Plug those numbers into the addition equation and solve for x. Then plug the value for x into the expression representing the largest number.
2(4x-6) + (3+3(2x+3)) + 4(x) = 90 --> 18x = 90 --> x = 5
4(6)-6 = 14
Maria owns an art studio and spent in supplies. She sells her paintings for
each. How many paintings does Maria need to sell until she makes a profit?
Explanation
Divide the total money spent by the cost of each painting.
Therefore, to make a profit, she needs to sell more than this amount. Since she can't sell a portion of a painting, the answer has to be the next nearest whole number ().
At the beginning of a race, a person's speed is miles per hour. One hour into the race, a person increases his speed by
. A half an hour later, he increases again by another
. If he finishes this race in two hours, what is the average speed for the entire race? Round to the nearest hundredth of a mile per hour.
Explanation
Recall that in general
Now, let's gather our three rates:
Rate 1:
Rate 2:
Rate 3:
Now, we know that the time is a total of hours. Based on our data, we can write:
This is miles per hour, which rounds to
.
Simplfiy the following expression;
Explanation
Multiply the numerators 2 x 6 x 4 = 48. Then multiply the denominators 3 x 8 x 12 = 288. The answer is 48/288. To simplify, divide both numerator and denominator by 48 to get 1/6.