Let's first break it down to the time 8 people need for one wall. That would be 10 minutes, right? If one person would have to do it in stead of 8, you'd expect him to take 80 minutes.
To paint 7 walls, he would nee 7x80 = 560 minutes. 10 people would do that 10 times faster, ie., 56 minutes.
I know puzzles like these always have a mindtrick. Did I miss anything?? ;-)
Let x = the total number of pennies her piggy bank can hold.
Then 2/3x = the number of pennies she started with
Then 2/3x - 80 = the number of pennies she has left after taking out 80 pennies.
Then 1/2x = the number of pennies she has left after taking out 80 pennies.
Build the equation.
2/3x - 80 = 1/2x
Subtract 1/2x from each side of the equation.
(2/3x - 80) - 1/2x = 1/2x - 1/2x
1/6x - 80 = 0
Add 80 to both sides of the equation.
(1/6x - 80) + 80 = 0 + 80
1/6x = 80
Divide both sides by 1/6.
(1/6x) / 1/6 = 80 / 1/6
x = 480
So, Linda's piggy bank can hold 480 pennies!
61/4 % converted into a decimal is 15.25
You would plug in the y=9 into the first equation and then have the expression 9=9x-9
. After going through the first steps of solving an expression you would get 18=9x. X=2. Then you would plug in the x value into the first expression to get y=9.
Since you know that point Y and point Z are equal distance form point F, you will need to know the distance between point Y, -1, and the distance between point X, -7. So, the total distance, after subtracting -1 from -7, is -6. So, you will then subtract another -6 from -7, to get -13, which is the coordinate of point Z.
