Calculating improper fractions

Question

Seam bought a record player for $7.25, his father has old albums which play at 33 and a third revolutions per minute. How many revolutions would an album make in twenty minutes

Answer 1

First convert 33 and 1/3 to an improper fraction. Multiply the denominator to the whole part and add the numerator. Place result over the denominator.

 

33 * 3 + 1 = 100

 

100/3

 

Multiply 100/3 by 20

 

100/3 * 20 = 2000/3 convert back to mix number by division. The remainder is the numerator of the fraction part.

 

666 and 2/3 revolutions

Answer 2

Hi Jade.  

 

First of all, the first sentence of this problem, or should I say the first phrase, does not figure into the problem at all.

 

What's important is the speed at which the albums rotate.

 

There are 33 1/3 revolutions per minute

In three minutes, there are 100 revolutions because 33 1/3 x 3 = 100

 

You need to convert the mixed number to an improper fraction.

 

For the numerator of the improper fraction, multiply the whole number by the denominator and then add the numerator.  The denominator of the improper fraction is the same as the denominator of the mixed number.

so

33 1/3 becomes (33 x 3 + 1)/3 = 100/3

 

In my example above 100/3 x 3 = 100

 

For this problem we want to know how many revolutions in 20 minutes

 

100/3 x 20 = 2000/3

 

To convert to a mixed number

divide numerator by denominator.  The answer is the quotient as the whole number with the remainder as the numerator of the fraction.

 

2000 / 3 = 666 remainder 2 ==> 666 2/3