As no digit is used twice then you have 4 choices for the first digit, but only 3 choices for the 2nd digit, 2 for the 3rd and just one for the 4th. 4 x 3 x 2 x 1 = 24 combinations.
The number is abcd(1) a=2b(2) d=a+b-2(3) a+b+c+d=15substituting eq. 1 into eq. 2d=2b+b-2d=3b-2Now, equation 3 is2b+b+c+3b-2=156b+c-2=156b+c=17Only possible answer for (b,c) is (2,5)a=2b ► a=4b=2c=5d=a+b-2 ► d=4+2-2 ►d=4The answer is 4254 ■
2993 of them.
There are 360 of them.
Twice while feeding the five thousand and at the last supper.
452, 894. None other that I can think of
This is missing some information. You mentioned the tens digit twice and didn't mention the ten thousands digit. One possibility is 87184.
(a)(a-2)(a+2)(2a) It can be: 2044 3156 4268
In order to get the greatest number we want to try and get the biggest possible numbers in the hundred thousands, ten thousands and thousand places. There is no rule against the hundred thousands digit being 9 so it must be 9. The ten thousand digit needs to be twice the tens so it must be 8 while the tens is 4. The thousands digit is divided by the units, and the number is even. So thousands must be 6 and the units must be 2. Thus the hundreds must be 7. The number is 986,742
2,241 because you double the digits
22621, 44742, 66863, 88984
1.382 OR 0.000 or 2831
The number that matches your criteria is... 998949