A boy can complete a piece of work alone in 10 days, but with the help of his friend he can complete it in 6 days. In how much time will his friend be able to complete the same piece of work alone?
Select the number from among the given options that can replace the question mark (?) in the following series.
3, 16, 5, 13, 9, 8?, ,?, 23, -8
Refer to the following letter, symbol series and answer the question.
L J + K – Y % T # U P
If all symbols are dropped from the series, which letter will be at the middlemost position in the newly formed series?