Question

what is the smallest two digit positive integer such that the product of its two digits is one-half the integer

Answer 1

Let x be the tens and y be the ones digits.

The product of the number is then: 10x + y

The product is 1/2, so you need to multiply the product by 2 and the number:

10x + y = 2(x+y)

10x + y = 2x + 2y

Subtract 1 y from both sides

10x = 2x + y

Subtract 2x from

Both sides

8x = y

X has to be 1 , which would make y 8

The product number becomes 18

Since the product is 1/2, multiply by 2:

18 x 2 = 36

3 x 6 = 18

The answer is 36