Answer:
a) 896 ways
c) 910 ways
Step-by-step explanation:
The question is a combination problem since it has to do with selection. In combination, if r object is selected from a pool of n objects, this can be done in nCr ways.
nCr = n!/(n-r)!r!
If from a group of 8 women and 6 men, a committee consisting of 3 men and 3 women is to be formed, we need to first calculate the total committee formed without any condition.
8C3 × 6C3
= 8!/5!3! × 6!/3!3!
= 8×7×6×5!/5!×6 × 6×5×4×3!/3!×6
= 56×20
= 1120ways
Now if;
a) two of the men refuse to serve together.
Since two men refuse to serve together, we will select 1 man from remaining 4 men since two has already been selected then select 3 from 8 women as shown.
4C1×8C3
= 4×56
= 224ways
Number of ways this can be done will be 1120-224 = 896ways
b) 1 man and 1 woman refuse to serve together
We need to choose 2 men from remaining 5 and 2 women from the rest of the men which is 7 as shown:
= (8-1)C(3-1) × (6-1)C(3-1)
= 7C2 × 5C2
= 7!/5!2! × 5!/3!2!
= 7×6×5!/5!×2 × 5×4×3!/3!×2
= 21×10
= 210ways
The number of ways this can be done will be 1120-210 = 910ways
