Question

How many members greater than 65000 can be formed by using the digits 5,6,7,8,9 once only.​

Answer 1

Answer:

Step-by-step explanation:

From left to right.

The first position can be filled only with 3 numbers: 6, 7 or 8. 3 possibilities.

Once the first position is filled, there are again 3 manners because now number 5 can be chosen, but we spent one number filling the first position.

So we are left with 2 numbers to fill the third position. We choose one of them.

Fourth position has only one option.

The first have 3 ways. The second 3 ways. The third 2 and the last only one.

Total ways are 3*3*2*1=18 ways.

A little different. If numbers are 6, 4, 7, 8. Try it. Hint: Start with 6 is different from 7 or 8.