## powerangers69 Group Title A four- digit number ( with no repetitions) is to be formed from the set of number ( 0,1,2,3,4,5,6,7). Find the probability that the number : a) is even 2 years ago 2 years ago

1. ParthKohli Group Title

You first find the number of four-digit numbers that may be formed from the above set.

2. telliott99 Group Title

Think of it this way, pick the numbers from right to left, least significant first.

3. ParthKohli Group Title

Can you do that? $8P4$ But there is something—we can't place a zero.

4. mihai Group Title

the probability is 50 %

5. powerangers69 Group Title

i did 6x6x5x4 ------- 7x7x6x5 ?

6. ParthKohli Group Title

Let's think of slots. _ _ _ _ Four slots. We have 7 choices for the first(there are eight numbers in the set, but we can't place a zero). 7 for the second too(we have a zero with us the second time). 6 for the third. (We already have two numbers filled out of eight). 5 for the fourth. (We have three filled).

7. ParthKohli Group Title

We multiply $$7 \times 7 \times 6 \times 5 \Longrightarrow 49 \times 30$$

8. powerangers69 Group Title

yes then? number of even numbers = 6x6x5x4 i that correct

9. ParthKohli Group Title

First find the number of four digit numbers you could make, then divide that by 2.

10. powerangers69 Group Title

um answer is not 1/2 though

11. mihai Group Title

every number that ends with a 0,2,4 and 6 is an even number, so if 4 out of 8 digits give you an even number wouldn't that be 50/50?

12. telliott99 Group Title

@ParthKohli see my post above. Make sense?

13. ParthKohli Group Title

Yup! That's correct!

14. powerangers69 Group Title

@ParthKohli answer is given as 780/1470 not 735/1470?