Math Is Fun Forum

I will remember how to work this one. Your calculations were accurate as they always are. Thank you! It is back to school for me tomorrow.

It won't take it and we both know it's right. I tried 18.6 and the 6 decimal place one too.

Here's the message that popped up when it said it wasn't right.

"Begin with the equation relating the first fish's weight to its length and girth, 20.5 = K21 (33)2^. Solve for K. Round K to 6 decimal places. Then calculate the width, w, of the second fish: w= K 23(30)2^."

Yes, I tried them both. It wants it to the tenth and I tried 17.1, then 17.14.  I thought my time was up, but one more try.

I will look again at the problem to see what else is there.

Meanwhile, I am working on this one:About the girth and weight of a fish.
The weight of a fish varies jointly as its girth and the square of its length. One fish weighed in at 21.7 lb and measured 34 inches long with 20 in girth. How much would a fish 31 inches long with 19 in girth weigh?
The fish would weigh approximately_____lb round to six decimal places. Round the weight to the nearest tenth, if necessary.
I am at this point and it won't "take."
K = 21.7/20 (34)2^
I keyed it on the calculator and it comes out 15 something, which is wrong..
Thanks and I will look for the other problem now.

It is exact as always. Thank you so much.
When I work a problem, it takes forever, because I write the steps down. I have spent hours on one problem before and wish I could solve them quickly.

You are exact. Thank you!

I hope this is the last finance problem:
A politician invested some money at 6% simple interest, and $32,000 more than four times the amount at 12%. The total annual interest earned from the investment was $36,240. How much did he invest at each amount?
Thank you again!

Thank you! All are correct as they always are.
Edited to add that this is also a good review before taking a math quiz. It is akin to a math library with answers.

Thank you!
How about that other one?
This one is about money too:
Othello Guaraz has a box of coins that he uses when playing poker with friends. The box currently contains 31 coins, consisting of pennies, dimes and quarters. The number of pennies is equal to the number of dimes, and the total value is $3.07. How many of each denomination of coin does Othello have?

The number of pennies, which is also equal to the number of dimes, is ____
The number of quarters is_______

Sorry, I left a decimal out. It is 2.50. My mistake.

Still working on problem.
In the first problem. There is something I am not doing right since i ended up with a decimal in the number of students.

2.50 x 4.50 (364-x) =1202.00
elimination of decimals by multiplication with 100.
100 x2.50 + 100 x 4.50 (364)-x = 100 x 1202.00=120200
250x + 450 x 364 - 450x =120200
163800 - 200x =120200
163800-163800-200x=120200-16380
-200x = -103900

-200x  =103900
_____________
-200      -200
 
The 200's cancel each other out (cross) out and something is wrong with the way i worked it. And I get a decimal which is not correct of course. It is all messed up.

It is correct!
I hope you are not getting tired. This is a lot of thinking.

The linear model below gives the approximate enrollment in thousands, for degree-granting institutions in a certain city, from the year 2003, where x = 0 corresponds to 2003, x =1 to 2004 and so on.
y = 0.2157x + 15.53

a. What is the projected enrollment for Fall 2012?
b. In what year is the enrollment projected to reach 18 thousand?
a. The projected enrollment for Fall 2012 is ____thousand
Round to nearest tenth.
There is a b. part, but cannot get it till this is typed in.
Thank you!

Thank you.
Last semester/this is the first math I've had since high school. I think it's called a math phobia.

Here is a word one: Looks like dabbling in chemistry.

A chemist has two solutions of H2SO4 (The 2 and 4 are tiny, not to the power but opposite.) One has a 40 % concentration and the other has a 25% concentration. How many liters of each solution must be mixed to obtain 50 liters of a 34% solution?

____ liters of the 40% solution and ____liters of the 25% solution must be mixed to obtain 34% solution of H2S04.
Round to nearest tenth. (anywhere that I list the H2S04, the 2 and 4 are tiny below.