Problema Solution
The number 2938 has this property: the thousands digit is even, the hundreds digit is odd, and all four digits are different. How many four-digit numbers have this property?
Answer provided by our tutors
thousandth digit has 4 choices: 2,4,6,8
hundredth digit has 5 choices: 1,3,5,7,9
tens digit has 8 choices (other than the 2 digits u put above...)
units digit has 7 choices (other than the 3 digits u put before it)
thus answer = 4 * 5 * 8 * 7 = 1120 numbers
1120 numbers have such property.