Video on Problem on Ages - shortcuts, tips and tricksProblems on Ages
Quick Tips and Tricks1) If the current age of a person be X, then
- age after n years = X + n
- age n years ago = X – n
- n times the age = nX
- If ages in the numerical are mentioned in ratio A : B, then A : B will be AX and BX
2) If sum of ages of x and y is A and ratio of their ages is p : q respectively, then u can determine age of y by using the formula shown below:
Age of y = | Ratio of y | × sum of ages |
Sum of ratios |
Points to Remember: - After reading the question, assume unknown age by some variable x.
- Convert the statements in the question into mathematical equations.
- Calculate the unknown by solving the equations and the obtained value must satisfy the conditions given in the problem.
Numerical on ages can be generally classified into four types: Type1: Calculate Present age
Q 1. What is John’s present age, if after 10 years his age will be 5 times his age 5 years back.
a. 6.2 years
b. 7.7 years
c. 8.7 years
d. 10 years
View solution Correct Option: (c)
1) Let John’s present age be x
2) John’s age before 5 years = (x - 5)
3) John’s age after 10 years = (x + 10)
We are given that, John’s age after 10 years (x + 10) is 5 times his age 5 years back (x – 5)
Therefore,
(x + 10) = 5 (x – 5)
Solving the equation, we get
x + 10 = 5x – 25
4x = 35
x = 8.75 years
Q 2. Rahul is 15 years elder than Rohan. If 5 years ago, Rahul was 3 times as old as Rohan, then find Rahul's present age.
a. 32.5 years
b. 27.5 years
c. 25 years
d. 24.9 years
View solution Correct Option: (b)
1) Let age of Rohan be y
2) Rahul is 15 years elder than Rohan = (y + 15). So Rahul’s age 5 years ago = (y + 15 – 5)
3) Rohan’s age before 5 years = (y – 5)
5 years ago, Rahul is 3 times as old as Rohan
(y + 15 – 5) = 3 (y – 5)
(y + 10) = (3y – 15)
2y = 25
y = 12.5
Rohan’s age = 12.5 years
Rahul’s age = (y + 15) = (12.5 + 15) = 27.5 years