Question

how many 3digit no can be made using the digits 1,2,3,4,6,7without repeat​

Answer 1

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A three digit even number is to be formed from given 6 digits 1,2,3,4,6,7.

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HTO

Since, for the number is to be even , so ones place can be filled by 2,4 or 6. So, there are 3 ways to fill ones place.

Since, repetition is not allowed , so tens place can be filled by remaining 5 digits. So, tens place can be filled in 5 ways.

Similarly, hundred's place can be filled by remaining 4 digits. So, hundred's place can be filled in 4 ways.

So,required number of ways in which three digit even numbers can be formed from the given digits is 4×5×3=60

Answer 2

Answer:

210

Step-by-step explanation:

Let us start filling these seats with the given numbers….. For the 1st seat, we have 7 options. So, any one of those 7 numbers will take the seat. Then, for the next seat, we have 6 options since one of the numbers has already taken a seat..similarly,we have 5 options for the last seat.

This means we can fill 1st seat by 7 diff ways, 2nd seat by 6 ways and the 3rd seat by 5 ways.. Hence, we can make 7×6×5(=210) different 3-digit numbers.

It doesn't asked that the numbers are even or odd so in a general manner this is the answer