"Each boy in a family has as many brothers as sisters, but each girl has twice as many brothers as sisters. How many children are in the family?"



Answer :

so b=boys
g=girls
g=1/2b
you woluld subtract 1 because not including the btother counting
b-1 brother=g
b-1=g
g-1=1/2b
subsitute
b-1-1=1/2b
add like terms
b-2=1/2b
mutiply both sides by 2
2b-4=b
add 4 to both sides
2b=b+4
subtract b
b=4

2 boys
b-1=g
4-1=g=3

4 boys,
3 girl

makes sense so if they are: bob, joe, sam, and bill,  then girls are sally, jill, and may then
bob has 3 brothers: joe sam and bill this equals number of sisters
may has sisters 1/2 of brothers, 2 sisters and 4 brothers 2 is 1/2 of 4

answer is 3 girls
4 boys