Question

the sum of the digits of a two-digit number is 15. the unit digit is one less than the tens digit. find the number. let x be the tens digit. show the equation!

Answer 1

Answer: 87.

Explanation:

Let x be the tens digit, then (x - 1) - unit digit.

x + x - 1 = 15

2x - 1 = 15

2x = 15 + 1

2x = 16

x = 16 ÷ 2

x = 8 - the tens digit.

8 - 1 = 7 - the units digit.

87 - the number.