Bank / Bcs /Others Competetive Exams Preparation
Age is to assume fixed period with which further conditions will be compared. For example taking 2000 as fixed year.
Basic Formulas
If the current age is x, then n times the age is ( nx ).
Example sum
Raju′s present age is 6 years. His brother age is 3 times that of Raju′s age. What is the age of after three years ?
Raju′s present age = 6 years
After three years Raju′s brother age = 6 * 3
= 18 years
Basic Formulas
If the current age is x, then age n years later/hence = x + n.
Example sum
Rajeev age after 15 years will be 5 times his age 5 years back. What is the present age of rajeev?
Let Rajeev present age be x years.
Rajeev age after 15 years = ( x + 15 )
Rajeev age 5 years back = ( x - 5 )
x + 15 = 5 * ( x - 5 )
x + 15 = 5x - 25
4x = 40
x = 40 / 4
x = 10
Basic Formulas
If the current age is x, then age n years ago = x - n.
Example sum
The present age of Ram is one sixth of his fathers present age. If the difference between their present ages is 35 years, then what is his father present age?
Let the present age of Ram be x.
Let the present age of father of Ram be y.
∴ x = ( 1 / 6 )y
If y - x = 35
y - ( y / 6 ) = 35
⇒ ( 6y - y ) / 6 = 35
⇒ 5y = 35 * 6
y = 42
∴ Father age = 42 years
Basic Formulas
The ages in a ratio a : b will be ax and bx.
Example sum
The ages of Ravi Rani are in the ratio of 3 : 5. After 9 years, the ratio of their ages will become 3:4. Find the present age of Rani?
Let Ravi′s age = 3x
Rani′s age = 5x
( 3x + 9 ) / ( 5x + 9 ) = ( 3 / 4 )
4 * ( 3x + 9 ) = 3 * ( 5x + 9 )
12x + 36 = 15x + 27
15x - 12x = 36 - 27
3x = 9
x = 9 / 3
x = 3
Rani′s age = 5x
= 15 years
The ages of Ravi Rani are in the ratio of 3 : 5. After 9 years, the ratio of their ages will become 3:4. Find the present age of Rani?
Let Ravi′s age = 3x
Rani′s age = 5x
( 3x + 9 ) / ( 5x + 9 ) = ( 3 / 4 )
4 * ( 3x + 9 ) = 3 * ( 5x + 9 )
12x + 36 = 15x + 27
15x - 12x = 36 - 27
3x = 9
x = 9 / 3
x = 3
Rani′s age = 5x
= 15 years