Find the highest power of 7 contained in 216! .a.36b.35c.34d.33

To find the highest power of 7 in 216!, we need to use the formula for finding the highest power of a prime number p in n!.

The formula is: n/p + n/p^2 + n/p^3 + ... until n/p^k < 1

Here, n = 216 and p = 7.

Let's calculate:

216/7 = 30 (ignoring the decimal part)

216/7^2 = 4 (ignoring the decimal part)

216/7^3 = 0 (since it's less than 1, we stop here)

So, the highest power of 7 in 216! is 30 + 4 = 34.

Therefore, the answer is c.34.