If 3/5 of all the brownies is 21, then 5/3 of 21 is the number of the brownies that Lauren brought in.
That probably sounded super confusing. When multiplying a number by a reciprocal of a fraction (a fraction where the numerator and denominator is reversed), the previous fraction multiplication is reversed.
Multiplying 21 with 5/3 will give us the original number of brownies.
Lauren originally brought 35 brownies.
5x = 50
Where x represents the (equal) amount of money each player contributed
As you can see, you can easily solve the equation above to get:
x = 10
Each player contributed $10 toward a $50 gift.
3.8+7.6+9.3+31+43+54+62+89+107+119+123+127=775.7
775.7/12=64.64166666666667
So the mean is 64.64
Here you are trying to find the hypotenuse. So you would take
5^2 (five squared) plus 12^2 (twelve squared) and add them using the equation a^2+b^2= c^2. Now you square 5 and 12 to get 25 and 144. You add them together and get 169. Take the square root of 169 and c. The square root on c will cancel out the squared (to the power of two) part leaving you with just c. And the square root of 169 is 13. So c (the missing length) is 13. C=13.
