Let the middle digit be x. Then, 2x = 10 or x = 5.So, the number is either 253 or 352. Since the number increases on reversing the digits, so the hundred's digit is smaller than the unit's digit. Hence, required number = 253.
There are total eight letters ∴ n(S) = 8PB = 8!As all vowels should come together we assume them as one letter. Here E, I, O and U together are taken as one, so the number of letter is 4 + 1 = 5 and it can be arranged in 5P5 = 5! ways and the vowels can be arranged in 4! ways among themselves∴ n(E) = 4! x 5!∴ P(E) = 4!5! / 8! = 4x3x2x5! / 8x7x6x5! = 4x3x2 / 8x7x6 = 1/14
EXAMIANS