Answer:
4 brothers and 3 sisters
Step-by-step explanation:
Let x be the number of brothers and y be the number of sisters in the family.
1. Each brother has x-1 brothers and y sisters. If each brother has as many sisters as brothers, then

2. Each sister has y-1 sisters and x brothers. If each sister has twice as many brothers as she has sisters, then

3. Solve the system of two equations:

Then

Answer:
$8.00
Step-by-step explanation:
Let's set up the equation first.
What do we know:
1. We have 6 friends spliting the costs of the gifts
2. After purchasing the gifts they have $42 in change
3. They originally had $90 to spend.
Equation:
6f + $42 = $90
Next: Subtract the $42 from each side and we are left with:
6f = $48
Divide both sides by 6 and we are left with
f = $8
Since f represented the cost each friend spent our answer is $8.00
Answer:
10y=27+7
10y=34
y=34/10
y=3.4
Step-by-step explanation:
Firstly 7 is added to 27
Then adding 7 and 27
Dividing 34 by 10