Math Homework Help

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September 30th 2010, 01:47 PM
inulled

Math Homework Help

- Four more than two thirds of a number is 22. Find the number.
- Find three consecration odd integers whose sum is 105
- A 100L tank now contains 240L of water. How long will it take to fill the tank using a pump that pumps 25L per minutes.

Any help?? (Doh)
September 30th 2010, 02:01 PM
pickslides

Quote:

Originally Posted by inulled

- Four more than two thirds of a number is 22. Find the number.

Solve $\frac{2}{3}x+4 = 22$

Quote:

Originally Posted by inulled

- Find three consecration odd integers whose sum is 105

Do you mean consecutive?

If so solve

$(2x+1)+(2x+3)+(2x+5)=105$
September 30th 2010, 02:01 PM
e^(i*pi)

Quote:

Originally Posted by inulled

- Four more than two thirds of a number is 22. Find the number.
- Find three consecration odd integers whose sum is 105
- A 100L tank now contains 240L of water. How long will it take to fill the tank using a pump that pumps 25L per minutes.

Any help?? (Doh)

1. Let x be the number you wish to find:

$\dfrac{2}{3}x + 4 = 22$ .

2. Let k be an integer. Since 2k is always even our first odd number is

$2k-1$ hence the next two odd numbers are $2k+1$ and $2k+3$

Hence $2k-1 + 2k+1 + 2k+3 = 105$ (you can simplify here)

3. The tank would already be overflowing, is there a typo in the question?
September 30th 2010, 02:02 PM
inulled

yeah
September 30th 2010, 02:04 PM
inulled

Quote:

Originally Posted by e^(i*pi)

1. Let x be the number you wish to find: $\dfrac{2}{3}x + 4 = 22$ . Solve for x

2. Let k be an integer. Since 2k is always even our first odd number is $2k-1$ hence the next two odd numbers are $2k+1$ and $2k+3$
Hence $2k-1 + 2k+1 + 2k+3 = 105$ (you can simplify here)

3. The tank would already be overflowing, is there a typo in the question?

im not too sure. this is a friend of mines homework... so i would say use your best judgment
September 30th 2010, 02:07 PM
Archie Meade

Quote:

Originally Posted by inulled

- Four more than two thirds of a number is 22. Find the number.
- Find three consecration odd integers whose sum is 105
- A 100L tank now contains 240L of water. How long will it take to fill the tank using a pump that pumps 25L per minutes.

Any help?? (Doh)

You can word them as follows....

$\frac{2}{3}x+4=22$

Then to find the number x, you need to remove the 4 and the 2/3 from the left hand side.

Hence, first subtract 4 from both sides, then multiply both sides by 3/2.

For the second one, only a certain 3 digits, increasing by 2, sum to 105.
It happens they are odd.

$x+(x+2)+(x+4)=105$

Add these up

$x+x+x+2+4=105$

$3x+6=105\Rightarrow\ 3x=105-6$

divide by 3 for the answer.

Has the tank been replaced by a bigger one?

the idea is... it takes 1 minute to get 25L into the tank.
therefore it takes 2 minutes to get (2)25L=50L into it,
it takes 3 minutes to get (3)25=75L into it etc

EDIT: We are supposed to be helping you, so it defeats the purpose to give solutions for a third party.
September 30th 2010, 02:08 PM
inulled

thanks man
September 30th 2010, 02:09 PM
skeeter

Quote:

Originally Posted by inulled

- Find three consecration odd integers whose sum is 105

let x = second odd integer

(x-2) + x + (x+2) = 105

solve for x, then determine (x-2) and (x+2)