- Messages
- 94
- Reaction score
- 66
- Points
- 28
thanks alot!ii) split into 2 cases
1. Thousand digit is 3
1st digit: 1 choice (can only be 3)
4th digit: 2 choices ( can only be 4 or 8)
2nd digit: 5 choices(any of the remaining)
3rd digit: 4 choices(any of the remaining)
2. Thousand digit is 4
1st digit: 1 choice (only 4)
4th digit 1 choice (only 8)
2nd digit: 5 choices
3rd digit: 4 choices
Total = (2*5*4) + (5*4)
iii) Split into 3 cases:
1. 1 digit number: 1 choice (5 only)
2. 2 digit number:
2nd digit: 1 choice ( 5 only)
1st digit: 7 choices
3. 3 digit number
3rd digit: 1 choice
1st and 2nd digit: 7 choices each
Total = 1 + 7 + (7*7)