Aptitude - Problems on Ages - Discussion
Discussion Forum : Problems on Ages - General Questions (Q.No. 13)
                   
                                       
                                13.
A person's present age is two-fifth of the age of his mother. After 8 years, he will be one-half of the age of his mother. How old is the mother at present?
 
                                    Answer: Option
                                                    Explanation:
                                                Let the mother's present age be x years.
| Then, the person's present age = | ![]()  | 
    2 | x | ![]()  | 
    years. | 
| 5 | 
![]()  | 
    ![]()  | 
    2 | x + 8 | ![]()  | 
    = | 1 | (x + 8) | 
| 5 | 2 | 
 2(2x + 40) = 5(x + 8)
 x = 40.
Discussion:
59 comments Page 3 of 6.
                
                        Malu said: 
                         
                        1 decade ago
                
                Ratio of present age of mother and son is 5:2.
After 8 years ratio becomes 2:1.
So x = 8*(2-1)/5-4 = 8.
Mothers age is 8*5 = 40.
                After 8 years ratio becomes 2:1.
So x = 8*(2-1)/5-4 = 8.
Mothers age is 8*5 = 40.
                        Simran said: 
                         
                        1 decade ago
                
                Hey please someone tell me why they have taken LCM only one side.
2X/5+8 = 1/2x+8.
It should be like this: 2x+40/5 = x+16/2.
                2X/5+8 = 1/2x+8.
It should be like this: 2x+40/5 = x+16/2.
                        Shravya said: 
                         
                        1 decade ago
                
                @Yuga how you simplified it can you please explain it. Your method is good but please can you tell how you calculated it.
                
                        Harish said: 
                         
                        10 years ago
                
                I have one doubt please tell me.
They asked about present age but we have added 8 years. How it will be the present age?
                They asked about present age but we have added 8 years. How it will be the present age?
                        Sanju said: 
                         
                        1 decade ago
                
                Why should it can't be 32 there is a possibility to get 32 as a answer? 
Can anyone give clear explanation about this?
                Can anyone give clear explanation about this?
                        Varun said: 
                         
                        1 decade ago
                
                Vijay, I was wondering about the same I think your right.. :)
The ans should be 40-8-32 present age of person's mother.
                The ans should be 40-8-32 present age of person's mother.
                        Vijay said: 
                         
                        1 decade ago
                
                Hey but does x=40 means after 8 years. They have asked for present age. Doesn't it should be x=32, the present age ?
                
                        Sumit said: 
                         
                        1 decade ago
                
                Person mother.
2 5.
1 2 (8 year hence).
Then mother's present age is.
M = (5*8*1)/(5*1) - (2*2).
M = 40.
                2 5.
1 2 (8 year hence).
Then mother's present age is.
M = (5*8*1)/(5*1) - (2*2).
M = 40.
                        Harihara said: 
                         
                        7 years ago
                
                32 will be the answer. In all the solutions 8 is added to find the age. So definitely 40 is not the answer.
                
                        Harshitha said: 
                         
                        6 years ago
                
                The correct answer would be 32 as it is mentioned in the question the present age, so it must be 40-8=32.
                
                     (3)
                
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