Question

Marty buys 12 ounces of granola.

a. What fraction of a pound of granola did Marty buy?
b. If a whole pound of granola costs $4, how much did Marty pay?

Answer 1

a. Fraction of a pound of granola is 3/4

b. Marty paid $3

Explanation:

a. First we have to know the relation between pound and ounces.

16 ounces are a pound ,so 1/16 pound is an oz

Marty buys 12 ounces of granola

In pounds this must be 12 x 1/16= 12/16=3/4

b. Costs of a pound is $4

Cost of this buy is 3/4 of $4,

=3/4 x 4 = $3

Answer 2

a. 3/4 Pounds b. $ 3 he paid

Explanation:

Topic: Rule of Three and Convertion Factors

You have to remember the concept of rule of three and know what is teh convertion factor for ounces to pounds.

The convertion factor is

`1 Ounce = 0.0625 Pounds`

Then you use the converstion factor to transform ounces to pounds using a rule of three, like this:

`1 Ounce = 0.0625 Pounds \\12 Ounces = x Pounds`

Remember how to find x?

`x = 12 Ounces * (0.0625 Pouns)/(1 Ounce) = 0.75 Pounds`

So you have that in pounds Marty 0.75 Pounds of Granola

Remember how to transform decimals to fractions?

you can multiply by a hundred and divide by hundred having that:

`0.75 * (100)/(100) = (75)/(100)`

by simplifying you hace that the fraction of pounds Marty Bought is 3/4

a. Marty bought 3/4 pounds of granola

b. if a whole pound costs $ 4 you can use another rule of three like this

`$ 4 = 1 Pound\\$ x = 0.75`

Solve again for x and you have that

`$ x = 0.75 Pounds * (\$ 4)/(1 Pound)`

so you have that Marty paid $ 3 for 3/4 pounds he bought