Latest Infosys Aptitude Question SOLUTION: a lady's age is between 50 and 70.each of her sons has many sons as his brothers. the sum of the sons and grandsons in the lady's age. what is her age?

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a lady's age is between 50 and 70.each of her sons has many sons as his
brothers. the sum of the sons and grandsons in the lady's age. what is her age?

Asked In Infosys asim (12 years ago)

Solved Vignesh Read Solution (9)

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Read Solution (9) :

Vignesh  (12 years ago)

Lady's age = 64

Let assume Lady has 'N' children.
Each child have (N-1) children. (Grandsons for that lady).

S0, total children = N+(N*(N-1))

By, putting N=6, we get 6+(6*(6-1)) = 36 childrens.
By, Putting N=7, we get 7+(7*(7-1)) = 49 childrens.
By, putting N=8, we get 8+(8*(8-1)) = 64 childrens.
By, putting N=9, we get 9+(9*(9-1)) = 81 childrens.

Here, Lady's age between 50 to 70.
So, answer is 64.

Lady age is 64 and she have 64 sons and grandsons in total.

Is this solution Helpfull? Yes (43) | No (3)  

harshita  (11 years ago)

If lady has 2 children the total children & grandsons are 4.
& if lady has 3 children the total children & grandsons are 9.That means perfect square.


since, in b/w 50 & 70 only 64 is perfect square, hence 64 is the answer

Is this solution Helpfull? Yes (24) | No   

Pargat Pal Singh  (12 years ago)

8 sons.
Each son has 7 sons ( grandsons of lady).

Total members = 8+8*7 = 64

64 years

Is this solution Helpfull? Yes (2) | No (6)  

nidhi jain  (12 years ago)

64...
As 8 sons will have 7 brothers implies each son will have 7 son's.
7*8=56 grandsons
56+ 8 sons =64

Is this solution Helpfull? Yes (1) | No   

sangram  (10 years ago)

no of sons 7 and no of grandsons 7*7=49 -> 7+49=56 years old

Is this solution Helpfull? Yes (1) | No (1)  

rahul.r.kalwar  (12 years ago)

number of sons and grandson's are consecutive so answer has to be the numbers which are consecutive.so numbers are 7 nd 8 ie:7*8=56 look now the ans is within 50 and 70 no other consecutive number lie within this range...:)

Is this solution Helpfull? Yes | No (3)  

nikitha reddy  (7 years ago)

let x be number of sons ,then total number of grandsons becomes x^2, now sum of sons and grandsons(x+x^2) which is equal to x^3, perfect cube between 50 to 70 is 64, so 64 is her age.

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mansi  (7 years ago)

if lady has 1 son then there is only 1 grandson

if lady has 2 sons then each of them having 1 son...

if 3 son then A B C
2 2 2 ->son beCAUSE A has 2 brother so A has 2 son similarlly for B AND C
then if lady has 3 son then sum of son and grand son 1+1+1+2+2+2=9

making perfact square b/w 50-60 8^2=64

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M J SHIVAYOGI  (7 years ago)

Let the number of sons be 'X'. Then the number of brothers one son has is 'X-1'. so the number of grand children each son has is 'X-1'. Therefore the sum of sons and grandsons is
= X + X ( X - 1)
= X + X^2 - X
= X^2 which is a perfect square.
the only perfect square between 50 and 70 is 64.
therefore the number of sons are 8 and grandsons are 7 x 8 = 56
the age of the lady is 8 + 56 = 64

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