ব্যাংক জব নিয়োগ – গণিত পরীক্ষা

Example 4 :
The present ratio of ages of P & Q is 4 : 6 . If the sum of present ages of P & Q is 50 years. Find the ages of P & Q before 4 years.
Answer:
Let ages of P & Q is x , so P & Q ages are 4x and 6x Gradually.
Now according to question Sum of present ages ,
4x + 6x = 50, 10x = 50, x = 5 years, (We got the value of x = 5)
And than the present age of P is = 4x = 4 x 5 = 20 years.
So, years ago the age of P = ( 20 – 4 ) = 16 years, and present  age of Q is = 6x = 6 x 5 = 30 years.
So, years ago the age of Q = (30 – 4 ) = 26 years.

Example 5 :
Reeya is 28 years old and Rajib is 12 years . In how many years will Reeya be twice  as old as Rajib ?
Answer :
Let Reeya be in x years . Then
( 28 + x ) = 2 ( 12 + x )
28 + x = 24 + 2x
x = 4 years .

Example 6 :
The ratio of ages of P & Q after 5 years will be 3 : 5 . If the sum of ages of P & Q at present is 38 years . Find the ages of P & Q before 5 years .
Answer :
Let the ages of P & Q are 3x and 5x respectively after 5 years .
( 3x – 5 ) + ( 5x – 5 ) = 38 years
6x – 10 = 38 years
8x = 48 years
x = 6
The ages of P after 5 years
= 6 x 3
= 18 years
Then the ages of Q after 5 years
6 x 5 = 30 years
The ages of P & Q before 5 years is
P = ( 18 – 10 ) = 8 years
Q = ( 30 – 10 ) = 20 years .

Example 7 :
Ratio of ages of M & N 4 years ago was 3 : 5. If the sum of present ages of M & N is 64 years than , Find the present ages of M & N.
Answer:
Let the ages is M & N 4 years ago are 3x and 5x.
Hence,
( 3x + 4 )+( 5x + 4 ) = 64 years,
= 8x + 8 = 64, = 8x = 56, x = 7.  ( we get the value of x).
So the age of M , 4 years ago  = 7 x 3 = 21years,
and the age of N, 4 years ago = 7 x 5 = 35 years.
Now the present age of M is = ( 21 + 4 ) = 25 years,
and present age of N is = ( 35 + 4) = 39 years.

Example 8 :
Ratio of ages of M & N 4 years ago was 3 : 5. If the sum of present ages of M & N is 64 years than , Find the present ages of M & N.
Answer :
Step1:  M : N = 3 : 5 , According to Question ( P + Q ) = 64 years.
Sum of both ages 4 years ago is ( 64 – 8 ) = 56 , (say that before age that’s why subtract)
Step2:  M = ( 56 / 8 ) x 3 = 7 x 3 = 21 years
and N = (56 / 8 ) x 5 = 5 x 7 = 35 years,
Step3:  present age of M = ( 21 + 4 ) = 25 years
and present age of N = ( 35 + 4 ) = 39 years.

Example 9 :
At present , the ratio between the ages of Anil and  Anu is 4 : 3 . After 4 years , Anil’s age will be 24 years . What is the age of Anu at present ?
Answer :
Let the present age of Anil and Anu is 4x years and 3x years respectively.
So , After 4 years Anil’s age ,will be 24 ,
4x + 4 = 24
4x = 20
x = 5
So , Anu present age is 3x = 3 x 5 = 15 years .

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