M4maths Previous Puzzles

11 Aug 2022 Permutation & Combinations

On the eve of Raksha Bandhan, Veena want to tie a Rakhi to her three brothers.If she has total seven silver and three gold Rakhis, then in how many different ways she can select Rakhis such that at least one gold Rakhi is there?

OPtion

1) 72
2) 80
3) 56
4) 84
5) 42
6) 85
7) 50
8) 90
9) 60
10) None of these

Solution

Veena may select Rakhis as (1 gold and 2 silver) or (2 gold and 1 silver) or (3 gold)
Required number of ways = (3C1 x 7C2) + (3C2 x 7C1) + (3C3) = 63 + 21 + 1 = 85
Corerect Option 6)

Correct Option: 6 Best Solution (0)