View all: NATIONAL BANK ( PO) | WRITTEN QUESTION (MATH) SOLVE | 2015
Correct Answer: ans: The number of children is 100 and amount of money 450 Tk.
Explanation:
Let, the number of children = x
and the amount of money each \gets = y Tk.
The total amount of money distributed = xy Tk.
so, According to question (x – 25) (y + 1.5) = xy……………………….. (i)
And (x+50) (y- l.5) =xy………………………… (ii)
We get from equation (i)
(x – 25) (y + 1.5) =xy
=> xy+ 1.5x – 25y-37.5 =xy
=> 1.5x – 25y = 37.5
=> 3x – 50y = 75 …………………(iii)
We get from equation (ii)
(x + 50) (y- l.5) =xy
=> xy-1.5x+50y-75 =xy
=> -1.5x + 50y = 75……………………….. (iv)
adding equation (iii) & (iv), we get
3x – 50y = 75
-1.5x + 50y = 75
1.5x =150
x = $\frac{150}{1.5}$ = 100
Putting the value of x in eqution (iii), we get
3x — 50y = 75
=> (3 x 100)-50y= 75
=> 300 – 50y = 75
=> – 50y = 75 – 300
=> – 50y = – 225
=> y=$\frac{-225}{-50}$
y = 4.5
Now putting the value of y in (iii)
=> 3x-50y = 75
=> 3x- (50) x (4.5) = 75
=>3x-225=75
=> 3x = 75 + 225
=> 3x = 300
=> x=$\frac{300}{3}$
x = 100
The number of children = x = 100 and
The total amount of money distributed = x $\times$ y = 4.5 x 100 = 450 Tk.