In this task you are given a list of numbers and you need to find the average of each two consecutive values. The average of two numbers a and b is calculated as: (a + b) /2. The output should be a list of the averages of each two consecutive values. A list is presented with two brackets and comma-separated values, like: [1,2,3].
Q: [-17, 68, -63, -23, 87, -81, 19, 92, -51, 19, 93, -75, -10, -21, -91]
A: 
[25.5, 2.5, -43.0, 32.0, 3.0, -31.0, 55.5, 20.5, -16.0, 56.0, 9.0, -42.5, -15.5, -56.0]