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].
One example: [-4, 7, 3]
Solution is here: [1.5, 5]
Explanation: To create the answer, we should first calculate the average of -4 and 7, that is: (-4 + 7 ) / 2 = 1.5, so the first element of the answer is 1.5. Then, we need to calculate the average of 7 and 3, that is: 5. So the second element of the answer is 5.

Now, solve this: [64, 13, 88, -99, -78, -76, -49, -69, 65, -52, 1, -18, -100, 21, -57]
Solution:
[38.5, 50.5, -5.5, -88.5, -77.0, -62.5, -59.0, -2.0, 6.5, -25.5, -8.5, -59.0, -39.5, -18.0]