Let n be a positive even integer. if the ratio of the largest coefficient and the 2 largest coefficient in the expansion of (1 + *)" is 11: 10.then, the number

Let n be a positive even integer. If the ratio of the largest coefficient and the 2 largest coefficient in the expansion of (1 + *)" is 11: 10.Then, the number of terms in the expansion of (1 +a)" is