ব্যাংক জব নিয়োগ – গণিত পরীক্ষা

Example 10 :
The total age of gangotri ,sabir, and bibhas is 96 years.10 years ago , the ratio of their ages was 2 : 4 : 5.What is the present age of bibhas?
Answer :
Step 1: Let 10 years before gangotri, sabir, and bibhas ages 3x, 4x, 5x years respectively.
Then ( 2x + 10 ) + ( 4x + 10 ) + ( 5x + 10 ) = 96,
= 11x = 66 = x = 6.
Step 2:  Bibhas present age is ( 5x + 10 ) = ( 5 x 6 + 10 ) = 40 years.

Example 11:
Present age of  Ramesh and Suresh are in ratio 5 : 6 respectively . Six years  hence , the  ratio of their ages will become 6 : 7 respectively . What is Ramesh present age in years ?
Answer :
Let the present age of  Ramesh and Suresh 5x and 6x years respectively.
So , 5x + 6 / 6x + 6 = 6 / 7
7(5x + 6) = 6 (6x + 6)
36x + 36 = 35x + 42
x = 6
Ramesh’s present age is 5x = 5 x 6 = 30 years .

Example 12:
Seven years ago , the age ratio of Sonu and Monu was 6 : 5 . Three years hence , the ratio of their ages will be 11 : 10 . What is Monu ‘s age at present ?
Answer :
Let the age of Sonu and Monu 7 years ago be 6x and 5x years respectively .
So, (6x  + 7) + 3 /(5x + 7 ) + 3   = 11 / 10
10 ( 6x + 10) = 11 ( 5x + 10 )
5x = 10
x = 2
So, Monu’s present age  = ( 5x + 7 ) = 17 years .

Example 13 :
twelfth years hence , Rahul will be just five times as old as he was 12 years ago , His present age is ?
Answer :
Let Rahul present age  be x years .
Rahul age 12 years ago  = ( 12 – x ) years and his age 15 years hence = ( 12 + x ) .
So , (12 + x ) = 5 ( 12 – x )
12 + x = 60 – 5x
6x = 48
x = 8
So , Rahuls present age is 8 years .

Example 14 :
The sum of present ages of a father and his son is 60 years, 6 years ago, father’s age was five times the age of the son. What will be After six years son’s age will be ?
Answer :
Step 1: let present age of son and father is x and (60 – x ) years, Then,
( 60 – x ) – 6 = 5 (x – 6 )
54 – x = 5x – 30
6x = 84
x = 14 years.
Step 2: Son’s age after six years is ( x + 6 ) = 14 + 6 = 20 years,

Example 15 :
Ratio of present ages of C & D is 4 : 6 . The present age of C is 40 years. Find the age of D after 6 years.
First we do Traditional way than we do shortcut way.
Answer :
Let the ages of C & D are 4x and 6x.
Hence,C = 4x = 40, = x = 10, ( So we get the value of x )
So the present age of D is = 6x = 6 X10 = 60 years, hence the age of D is  after 6 years 60 + 6 = 66 years.

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