Question 141300
Let the units number be u; the tens be t.
A) t+u=8
B) 10u+t=10t+u+54
.
A) u=8-t
B) 
10(8-t)+t=10t+8-t+54
80-10t+t=9t+62
80-9t=9t+62
18t=18
t=1
u=7
The number is 17.
.
Check:
71-17=54
.
Ed