The work capacity of A is three times more than that of B. Both of them together can complete a work in 15 days. In how many days will A alone complete that work?

In how many different ways can the letters of the word 'LEADING' be arranged in such a way that the vowels always come together?

A, B and C can do a work in 20, 30 and 60 days respectively. In how many days can A complete the work, if he is assisted by B and C on every third day?

In how many different ways can the letters of the word EDUCATION be arranged so that the vowels come together?

A man has 7 relatives (4 women and 3 men). His wife also has 7 relatives (3 women and 4 men). In how many ways can they invite 3 women and 3 men so that 3 of them are man's relatives and 3 of them ar…

How many words can be formed from letters of the word 'ULTRA' so that the vowels never come together?