MaxWong

$\dfrac{\text{3 pounds}}{\text{0.90}}=\dfrac{\text{10 pounds}}{x}\\ \text{3x pounds} = \text{9 pounds}\\ 3x = 9\\ x = 3$

10 pounds will cost $3.

My weight is about 100 pounds and it would cost me about $30. LOL

Diameter of the Earth  = 12742 km.

Perimeter of the Earth = $\pi$ x diameter = 12742$\pi$km.

LOL :P

:)

Btw I think it has already been a few days ago when I last logged into the forum? 

I didn't leave the forum :)

Good question though.

$\text{Let }x = 1991\\ \dfrac{1}{1991} + \dfrac{1992\times 1990}{1991} - 1992\\ = \dfrac{1}{x} + \dfrac{(x+1)(x-1)}{x}-(x+1)\\ =\dfrac{1}{x} + \dfrac{x^2 - 1}{x} - (x+1)\\ = \dfrac{x^2 +1 - 1}{x }-(x+1)\\ = \dfrac{x^2}{x} -(x+1)\\ = x - x - 1\\ = -1$

Substitution is always brilliant :)

1 loaf of bread = 1/4 cup of oil.

5 loaf of bread = 5 x 1/4 cup of oil = 1 1/4 cup of oil.

There are still 5/8 cup of oil left

Therefore add them up: 1 1/4 + 5/8 = 1 2/8 + 5/8 = 1 7/8

Judy started with 1 and 7/8 cups of oil.

$m(z+9) - m(z) ; m = z^2\\ = (z + 9)^2 - z^2\\ = z^2 + 18z + 81 - z^2\\ = 18z + 81$

You mean the A 'flat' 9 sus4 chord? :)

I do know something about music :)

sqrt(pi) ~= 1.77245385090551602729.

:)

78354962*776625 = 60852422363250 according to this calculator.