"SUCESS".indexOf('S') + "SUCCESS".lastIndexOf('S')
6
Reason — indexOf() returns the index of the first occurrence of the specified character within the string and lastIndexOf() returns the index of the last occurrence of the specified character within the string. Since a string begins with index 0, the given methods are evaluated as follows:
"SUCESS".indexOf('S') + "SUCCESS".lastIndexOf('S')
⇒ 0 + 6
⇒ 6