Y-x =17
y = -x + 17
substitute this into the second equation
y = 4x + 2
-x + 17 = 4x + 2
0= 5x -15
15/5 = 5x/5
3 = x
Add 3 standard deviations above and below the mean to get the range in which 99.7% of the data in a normal distribution will fall
6.5 + 4.5 = 11
6.5 - 4.5 = 2
So 2 to 11 ounces would be the interval
0.77875...
which, I'm assuming, they want you to round to the nearest hundredth? So, .78?...
