(a) There are total of 10 persons of which P1 is always selected and hence P4 and P5 are not be included in the arrangement Now, person left = 10 - 3 = 7 (as P1 is already selected and P4 and P5 are not selected) ∴ To select 4 persons from 7 persons total ways = 7C4 Also, these 5 persons can be arranged in 5! ways ∴ Required ways of arrangement = 7C4 x 5!