At the school store, 5 pens sell for $1.25. Which proportion will help find the cost of 12 pens?
a. 5/12=1.25/x
b. 5/12=x/1.25
c. 5/x=12/1.25
d. x/5=12/1.25
I say its c
5 pens / 12 pens = 1.25 dollars/x dollars
It helps to write the units, pens and dollars.
so
I claim a is correct
although I myself would have written the same thing as
5 pens/1.25 dollars = 12 pens/x dollars
which comes out the same
5 pens cost 1.25$
1.25/5=0.25$ Price of one pen
12*0.25=3$ Price of 12 pens
To find the cost of 12 pens, we can set up a proportion using the given information.
Let's define x as the cost of 12 pens.
We know that 5 pens sell for $1.25.
This can be expressed as the ratio:
5 pens / $1.25 = 12 pens / x
To find the proportion that will help find the cost of 12 pens, we rearrange the equation to isolate x, which represents the cost of 12 pens:
(x / 12 pens) = ($1.25 / 5 pens)
So, the proportion that will help find the cost of 12 pens is:
(x / 12) = (1.25 / 5)
What are your choices?
What do you think the answer is?