In this task, you are given a list. This list contains many lists of integers. The list is several items written within a []. Your task is to find the maximum number among the members of each inner list. The output should be a list comprised of the maximums with the same order as the internal lists.
[[15, 28, 31, -77, -149, -140, 48], [-50, -108, -87, 32, -108], [-138, -7]]