Problem: the sum of a two digit number is equal
The sum of the digits of a two digit number is equal to 1/7 of the number,
given that the tens digit is more than the units digit by 4,what is the number?
We have a number, AB, such that B = x, and A = x + 4.
Also, x + (x + 4) = AB/7
AB/7 = 2x + 4
(AB/7) * 7 = (2x + 4) * 7
AB = 14x + 28
Select values for x and solve.
x = 1 The number would have to be 51
14(1) + 28 = 14 + 28 = 42 No
x = 2 The number would have to be 62
14(2) + 28 = 28 + 28 = 56 No
x = 3 The number would have to be 73
14(3) + 28 = 42 + 28 = 70 No
x = 4 The number would have to be 84
14(4) + 28 = 56 + 28 = 84 <<<<<<
8 + 4 = 12
84/7 = 12
Answer: the number is 84