How many X's are there in the following series which are immediately preceded by E and immediately followed by L? P E X R T N E X L R E N X U P E X T A X F E X L N E X

Refer to the following letter series and answer the question (counting from left to right): C B A S N U C O M D K I F J H A I P B E B H How many such consonants are there, each of which is immediately preceded by a consonant and also immediately followed by a consonant?

Refer to the given series and answer the question that follows (All numbers are single digit numbers only). Counting is to be done from left to right. (Left) 58561868515888941618425432126 (Right) How many such odd digits are there, each of which is immediately preceded by an even digit and also immediately followed by an even digit?