A four-digit number with all different digits has the
sum of its digits is 13. Find the number if the thousands
place is double the units place and the tens place is
one more than the hundreds place.
Let the number be "ABCD"
the sum of its digits is 13.
A+B+C+D=13
the thousands place is double the units place
A = 2D or D =
the tens place is one more than the hundreds place.
C = B+1 or B = C-1
Substitute in A+B+C+D=13 and solve for A
All digits are between 0 and 9 inclusive
Substitute:
Multiply through by 3
Subtract 28 for all three sides
Divide through by -4 reversing inequalities
The only digit between 1.75 and 0.25 is 1
Therefore C = 1 and since
A = 8
and
B = C-1 = 1-1 = 0
and
D = = = 4
So "ABCD" = 8014
Edwin