-- Carefully cut <em>each bar into 6 equal pieces</em>.
There are (5 x 6) = 30 pieces all together.
Each piece is 1/6 of a bar.
-- Each child gets 5 of the pieces.
That's the same as <em>5/6 of a whole bar</em>.
(6 children) x (5 pieces) = 30 pieces. It works out. yay !
(2x-20)/3 = 2x start by multiplying both sides by 3
For the selection to be 10, there has to be at least 3 girls. So there's a 1/4 chance of 3 girls picked, 1/4 4 girls, 1/4 5 girls and 1/4 6 girls. Because the sum of people has to be 10, if 4 girls are picked, to make 10 people there is a 1/1 chance of 6 boys. 1/4 * 1/1 = 1/4. So 1/4 chance of 4 girls and 6 boys
Super easy. Take the function, and replace X with Y and Y with X. For example, if Y=12/x, then the inverse would be X=12/Y. Now solve for Y, so XY=12, the Y=12/x.