Question

The worth of a collection of pennies is directly proportional to the weight of the collection. if a collection weighing 8.8 oz. is worth 1$, how much would a collection of pennies weighing 5 lbs. be worth? - For the life of me i can't figure this story problems out and i have been going at it for a couple hours now..please help!!!

Answer 1

in case of direct proportion:

x1 y1
------ = ------
x2 y2

here x1 = 8.8 oz x2 = 5 lbs
y1 = 1$ y2 = we have to find out

Answer 2

To start, convert 5lb to oz. (or vice versa).

5lb = 80 oz.

The problem states that the collection is $1 for every 8.8oz or $1/8.8oz.

By using this, we can multiply 80oz. by this fraction so:

($1/8.8oz)*(80oz) = $9.09

Answer 3

now 5 lbs = 80 oz

so

8.8 1
------ = ------
80 y2

cross multiplying we get
8.8 * y2 = 80
y2 = 80/8.8 = $ 9.09

Answer 4

You guys are amazing! but i have one more stupid question..how do you convert lbs. to oz?

Answer 5

1 lb = 16 oz

so 5 lbs = 5 x 16 oz = 80 oz

u hv to know this conversion or u can type it in the google bar as " 5 lbs to oz" and it will give u the conversion

Answer 6

I used www.wolframalpha.com, like Harkirat said google does the same thing.

Answer 7

Awesome! i wish my teacher would be as clear!

Answer 8

we r here to clear things if u want, for direct proportions/variations use the formula I gave u above and substitute the values and u will get yr ans...

By the way, for Inverse proportions, the formula is x1*y1 = x2*y2

Answer 9

That is so helpful! Thank you so much! How about joint variation/proportions?

Answer 10

give me a question n i will explain.....

by th way, i need fans, can u become one pls !!! ( :})

Answer 11

lol o.k.!
Here is the problem: the size of an uncomressed TIFF graphics file is jointly proportional to it's width and it's height. a file measuring 2288 x 1712 pixels has a size of 4.2 MB. What would be the size of a graphics file with a width of 800 pixels and a height of 2000 pixels?

Answer 12

here it says "jointly proportional to "
so I say

here x1 = 2288 x 1712 x2 = 800 x 2000
y1 = 4.2 MB y2 = ???

so

2288 x 1712 800 x 2000
-------------- = --------------
4.2 y2

cross multiplying we get
2288 * 1712 * y2 = 4.2 * 800 * 2000
y2 = 6720000/3917056 = 1.72

Answer 13

Wow..it's always so amazing to me when people get this stuff, math has never been my strong suit lol! Thank you for all the help!!! you make it look so easy!

Answer 14

another medal for me????

Answer 15

lol..i gave you one earlier, and it is not letting me click the button again..if there is another way i definitly will!!!!

Answer 16

hv u become my fan yet !!!

Answer 17

of course! :)