AboutSurajit Basu Expertise I can answer questions which are mathematical, logical, or wordplay related.
I am not good at highly creative problems, or riddles.
Experience I regularly do puzzles, and help out friends, teenagers. I read books written by Martin Gardener. I love the puzzles and Easter eggs in Douglas Hofstadter's Godel, Escher, Bach: an enternal golden braid.
Publications A few examples of my writing:
http://surajitbasu.sulekha.com/blog/post/2006/04/the-journey-down-the-number-line.htm
Education/Credentials B. Tech. ( Computer Science), IIT Kanpur, India
MBA ( Post-Graduate Diploma in Business Management), (Finance, Systems), IIM Calcutta, India
Question QUESTION: in one family there are several children in which each boy has as many sisters as he has brothers but each girl has brothers which are twice of sisters she has then how many brothers and sisters are they?
ANSWER: n one family there are several children in which each boy has as many sisters as he has brothers but each girl has brothers which are twice of sisters she has then how many brothers and sisters are they?
Suppose there are B boys and G girls.
We know each boy has as many sisters as he has brothers.
How many sisters does each boy have?
Of course, it is
.. think ....
Each boy has G sisters.
How many brothers does each boy have?
Of course, it is
.. think ....
Each boy has (B-1) brothers.
We know each boy has as many sisters as he has brothers.
So, G = B-1.
We know each girl has brothers which are twice of sisters.
How many brothers does each girl have?
Of course, it is
.. think ....
Each girl has B brothers.
How many sisters does each girl have?
Of course, it is
.. think ....
Each girl has (G-1) sisters.
We know each girl has brothers which are twice of sisters.
So, B = 2 * ( G-1)
We also know ( Earlier) that G = B-1.
Thus, B = 2 * ( G-1)
Replacing G with B-1 we get
B = 2 * ( B-1 -1)
i.e. B = 2B - 4
i.e. B = 4.
So, G = 3.
Try it out imagining you are one of the brothers, and one of the sisters.
Follow up at surajit@gmail.com
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QUESTION: a little girl i know sells oranges door to door one day on her rounds she sold 1/2 an orange more than half her oranges to the first customer. to the second customer she sold 1/2 an orange more than half of the reminder and to the third and the last customer she sold 1/2 an orange more than half she now had ,leaving her none.
can you tell the no of oranges she originally had? she never had to cut an orange.
explain me question and give ans.
Answer A little girl sells oranges door to door one day on her rounds.
Suppose she had A oranges. .. and equally importantly, you like algebra!
She sold 1/2 an orange more than half her oranges to the first customer.
So, she sold 1/2 + A/2 oranges to the first customer.
What did she have left?
think now, and look later...
Remainder after 1st customer= A - (1/2 + A/2) i.e. A/2 - 1/2.
To the second customer she sold 1/2 an orange more than half of the remainder.
how would you express that?
think now, and look later...
1/2 + ( A/2 - 1/2)/2
What did she have left?
think now, and look later...
Remainder after 2nd customer= ( A/2 - 1/2) - (1/2 + ( A/2 - 1/2)/2)
i.e. A/2 - 1/2 - (1/2 + A/4 - 1/4)
i.e. A/4 - 1/2 - 1/2 + 1/4
i.e. A/4 - 3/4
To the third and the last customer she sold 1/2 an orange more than half she now had
i.e. 1/2 + ( A/4 - 3/4)/2
What did she have left?
think now, and look later...
Remainder after 2nd customer= ( A/4 - 3/4) - (1/2 + ( A/4 - 3/4)/2 )
i.e. A/4 - 3/4 - (1/2 + A/8 - 3/8)
i.e. A/8 - 3/4 - 1/2 + 3/8
i.e. A/8 - 7/8.
this is 0 ( leaving her none);
so, A/8 = 7/8; i.e. A = 7
Now, let us suppose you do not like algebra!
Let us start at the end!
To the third and the last customer she sold 1/2 an orange more than half she now had ,leaving her none.
So, how many did she have at this stage before selling?
All she had was the same as half her oranges, and a half!
So, she had 1 orange, right?
To the second customer she sold 1/2 an orange more than half of her oranges and was left with 1 orange.
So, how many did she have at this stage before selling?
she sold half her oranges, and a 1/2 .. and she was left with 3!
All she had was the same as the same as half her oranges, and 1 and a 1/2.
So, she had 3 oranges, right?
To the first customer she sold 1/2 an orange more than half of her oranges and was left with 3 orange.
So, how many did she have at this stage before selling?
she sold half her oranges, and a 1/2 .. and she was left with 3!
All she had was the same as the same as half her oranges, and 3 and a 1/2.
So, she had 7 oranges, right?
