View all: SONALI & JANATA BANK LTD (SO) IT WRITTEN QUESTION (MATH) SOLVE | 2018
Correct Answer: 24
Explanation:
Let. Tenth digit is x and unit digit is y
The number = (10x + y)
According to first condition, 4(x + y) = 10x + y ………(i)
And second condition, (10x + y) + 18 = 10y + x………………… (ii)
From equation (ii),
10x+4+y+18 = 10y +x
=> 9x-9y = -18 . .
=> 9y – 9x = 18
=> 9(y-x) = 18
= (y – x) = $\frac{18}{9}$ = 2
=> y – x = 2
so, y = x + 2 ……….(iii)
From equation (i) we get 4(x + y) = 10x + y
=> 4x + 4y = 10x + y
=> 3y =6x
=> y = 2
so, y = x+2………….(Iv)
From equation (i), we get 4(x+y) = 10x+y
=> 4x+4y = 10x+y
=> 3y = 6x
=> y = 2y
=> x+2 = 2x [ putting the value of y]
so, x=2
Now, putting the value of x in equation (iv) we get
y= x+2
=> y = 2+2 =4
so, y=4
The number is |(10x+y) = (10×2)+4 =20+4 =24