It takes 2 1/4 kilometers of thread to make 3 1/2 boxes of shirts. How many kilometers of thread would it take to make 8 boxes?

Respuesta :

[tex]5\frac{3}{7}[/tex] Kilometers of thread.

The key to solve this problem is using the rule of three.

We have to change mixed number to improper fraction in order to solve the problem.

A mixed number is a number formed by an integer and a proper fraction (one whose quotient is less than 1).

An improper fraction  is one whose denominator is less than its numerator.

To change a mixed number to an improper fraction:

1. Multiply the whole number by the denominator and add to the numerator.

2. The denominator of the mixed number is unchanged.

It takes [tex]2\frac{1}{4}[/tex] kilometers of thread to make [tex]3\frac{1}{2}[/tex] boxes of shirts. How many kilometers of thread would it take to make 8 boxes?

We need to change [tex]2\frac{1}{4}[/tex] and [tex]3\frac{1}{2}[/tex] to an improper franctions:

[tex]2\frac{1}{4}=\frac{(2)(4)+1}{4}=\frac{9}{4}[/tex]

[tex]3\frac{1}{2}=\frac{(3)(2)+1}{2}=\frac{7}{2}[/tex]

To calculate how many kilometers of thread would it take to make 8 boxes, we use the rule of three:

9/4 Km of thread -------------> 7/2 boxes of shirts

                    x     <-------------  8 boxes of shirts

[tex]x = \frac{(\frac{9}{4})(8)}{\frac{7}{2}}= \frac{19}{\frac{7}{2}}\\x=\frac{38}{7}[/tex]

Convert the improper fraction 38/7 to a mixed number:

1. Divide the numerator by the denominator.

38÷7 = 5 and a remainder of 3

2.  5 become the whole number, the remainder is the numerator, and the denominator is unchanged.

38/7 = 5 3/7

It would take 5 3/7 kilometers of thread make 8 boxes of shirts.