Word Problem 6:

Problem 6: Sam and Sarah are siblings. Sam has as many brothers as sisters. Sarah has twice as many brothers as sisters. How many boys and girls are in the family? (basic mathematics for general public)


Here we keep in mind that Sam is a Boy himself He has brothers and sisters equale in number i-e if he has ‘b’ brothers and ‘g’ girls then b=g. But in his case he is to be subtracted from boys list. So, the final equation for him will be;

b-1=g ----(1)

Now we should keep in mind as well that Sarah is a girl. She has sisters double in number to brothers i-e if she has ‘b’ brothers then her sisters will be ‘2g’. Or she has 2 sisters equal to one brother i-e 2g= b. But because she is a girl hereself, she is to be subtracted from number of girls. So the final equation will be;


b=2g-2 --(2)

Solving equation 1 & 2 simultaneously,

From eq 1 we get;


put this value of b in eq 2


\Rightarrow g=3

So, there are 3 girls in the family.

Put value of g in b=1+g

 we get;

b= 1+3=4

or b= 4

i-e There are 4 boys in the family



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