Question

The sum of the two digits of a number is 16. The number formed by reversing the digits is 18 more than the original number. Determine the original number. Let t = the tens digit, u = the units digit, and u + t = 16. Which of the following equations would complete the system? 9t - 9u = 18 9u - 9t = 18 tu = ut + 18

Answer 1

The correct answer:

9u - 9t = 18

Answer 2

9u-9t=18

original no. is 10t+u
reversed no. is 10u+t

so its (10u+t)-(10t+u)=18
which gives 9u-9t=18