The number is 43.
Let, the unit digit = x and
The tenth digit = y
The number is 10y + x
According to the first condition of the question
(x + y) + 5 = 3y
x = 3y — y —- 5
x = 2y – 5 ———— (i)
Again, after the digit is interchanged then, Unit digit will be y and tenth digit will be x and the
interchanged number 10x + y.
According to the Second condition of the question
(10y+x) – (10x+y) = 9
=>9y—9x=9
=>9(y—x)=9×1
=>y—x = 1 [Divide both side by 9]
=>y—(2y—S) =1 [From 1]
=>y-2y+5=l
=>y—2y= 1—5
=>y=4
Putting the value of y in (i) we have,
x=2.(4)-5=8—5=3
The number= 10y+x=(10x 4)+3 =43.
ans: Increment is 125 tk. salary at beginning is 4000 TK
After 8 years salary is 5000 tk.
After 4 years salary is 4500 tk.
4 years salary difference = 500 tk.
1 years salary difference = $\frac{500}{4}$ = 125 tk.
At beginning, salary was [4500 = (125 x 4)] = 4000 tk.
