In a letter series a _ _ bb _ a _ _ bbaacc _ _ a the missing letters in the proper order are

The missing letter in the sequence Q, N, K, ?, E is –

The missing number in the series is: 4, 18, 48, ?, 180

Find the missing numbers in the given series 1, 2, 3, 14, 5, 34, 7, ?, ?

Find the missing number in the given series 5, 16, 49, 104, ?

Find the missing number in the given series 6, 14, 36, 98, ?