Posted by **alejandro** on Monday, August 5, 2013 at 2:00pm.

A security code used to consist of two odd digits, followed by four even digits. To allow more codes to be generated, a new system uses two even digits, followed by any three digits. If repeated digits are allowed, the increase in the number of possible codes is____

Answer: Old code: 5x5x5x5x5x5=15325

New code: 5x5x10x10x10=25000

The increase in the number of codes is 9375.

I don't understand why they use 5's and 10's!!!Please somebody can explain me this!!!

- math30 -
**Reiny**, Monday, August 5, 2013 at 3:10pm
how many **even** digits are there from 0 - 9 ??

there are 5

how many digits are there from 0 to 9 ?

there are 10

so you have 5 choices as the first digit, 5 choices again for the second digit, 10 choices for the 3rd digit, etc

- math30 -
**alejandro**, Monday, August 5, 2013 at 3:31pm
Thanks, but what about the odd number?

- math30 -
**Steve**, Monday, August 5, 2013 at 4:07pm
let's see. You know there are 10 digits

You know there are 5 even digits.

asking now how many odd digits there are is the same as holding out both hands, and when someone says, "This one is your left hand," you ask, well, which one is my right hand?

## Answer this Question

## Related Questions

- math - 1. a door code is made up of six unique digits the last digit is 8. 2....
- gemetry - An identification code is to consist of two letters followed by six ...
- Math - 1.) A security code has seven characters. Each code begins with two ...
- College probability and statistics - The current license plates in New York ...
- math - I am thinking of a two-digit number in which the sum of the digits is 9 ...
- math: probability - A locker combination has three nonzero digits, and digits ...
- Math - An identification code is to consist of six letters followed by three ...
- Math problems Help Please!!!!!! - i am a four-digit number with the digits in ...
- Math problems - i am a four-digit number with the digits in order. my first two ...
- MATH - What is my number if the hundreds digit is less than the tens digit and ...