Each piece of information in the "story" gives you an equation. You need to find 7 equations (for the seven unknown ages) to solve the question.
For example, letting A, P, M, V, C, O, and Op be the age of each mooncalf, the first piece of information is that the siblings are separated by a total of 11 years, so we know that
A - Op = 11.
See if you can find the rest.