Sadie has $1 worth of nickels and dimes. She has twice as many nickels as dimes. Write a system of equations that could be used to determine the number of nickels and the number of dimes that Sadie has. Define the variables that you use to write the system.

The stem-and-leaf plot shows the heights in centimeters of teddy bear sunflowers grown in two different types of soil. soil a soil b 5 9 5 2 1 1 6 3 9 5 1 0 7 0 2 3 6 7 8 2 1 8 3 0 9 key: 9|6 means 69 key: 5|8 means 58 calculate the mean of each data set. calculate the mean absolute deviation (mad) of each data set. which set is more variable? how do you know?