Question

4. What is the probability that a randomly selected integer number between 1 and 1000 will not have a digit 7?

Answer 1

subtract \[1000-7=your answer\] You know that 7 is put between the numbers only once... so subtract 1000 and to get your probability!!!

Answer 2

There are 1000 numbers from 1 to 1000.
How many of them have the digit 7?

Answer 3

oops I read the question wrong my bad...

Answer 4

? (For instance, 23 does not have a digit 7, but 73 and 277 both do.)

Answer 5

You need to count the numbers form 1 to 1000 that have the digit 7.

Answer 6

why don't you say 10,20,30 and count how many numbers between each of them have a 7. it'll be faster that way

Answer 7

1-P(one 7)-P(tewo 7's)-P(3 7's)

Answer 8

Here's a way of starting the count.
Separate the numbers from 1 to 1000 into groups of 100.

For example, start with integers from 1 to 100.

Answer 9

btw, i assume that between means not inclusive of the end points 1 & 1000.

Answer 10

1-10 how many 7's?
10-20 how many 7's?
now keep doing that in sections of 10

Answer 11

isn't there any formula to do so? manual is the only way to count the number of 7's between 1- 1000?

Answer 12

no, that's the hard and confusing way.
first, how many numbers total?

Answer 13

make your own formula if you can...

Answer 14

From 1 to 100:
7
17
27
37
47
57
67
All 70's, there are 10 of them
87
97
That is a total of 19.

Answer 15

@pgpilot326 it's not confusing if you write the numbers on a sheet of paper...