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Maths Puzzle
Logical Reasoning
Coding Decoding
HOW MANY FOUR DIGIT NUMBERS CAN BE FORMED FROM 1,2,3,4,5,6,7 WHICH IS GREATER THAN 3400?
Read Solution (Total 4)
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- 560 four digit numbers can be formed without repetition.
No. of 4 digit numbers where first digit is 4,5,6 or 7.
==> 4* 6C3 = 4 * 120 = 480
No. of 4 digit numbers where first digit is 3..
second place can be filled by 4,5,6,or 7.
==>no. of possible numbers = 4* 5C2
==> 4 * 20 = 80
total no. of possible numbers formed from 1,2,3,4,5,6 and 7
and greater than 3400 = 480 + 80 = 560
- 12 years agoHelpfull: Yes(3) No(4)
- There is no condition that digits can not be repeated.
Number of nos starting with 34 i.e
34XX = 1*7*7 = 49
Number of nos starting with 4,5,6,7 = 4*7*7*7
so total possible FOUR DIGIT NUMBERS that CAN BE FORMED FROM 1,2,3,4,5,6,7 WHICH IS GREATER THAN 3400 = 49+28*49= 49*(1+28) =49*29= 1421
so 1421 numbers - 12 years agoHelpfull: Yes(3) No(3)
- Four digit Number > 3400=3411 to 3477( using the digit 1 to7)
Thus No. of digits with the given conditions are 67 numbers
- 12 years agoHelpfull: Yes(0) No(5)
- Sanjana, 3512 is also grater than 3400. So check your answer
- 12 years agoHelpfull: Yes(0) No(4)
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