Question

Please help with #10 and #11

Answer 1

Divide ans Subtract 
Assuming it was just one whole family so 
51 - 6 = $45
45 ÷ 4.5 = (Answer for number 10)There was 10 people on the whole family 

Answer 2

10) Let x be the number of people of this family:
The total paid with the parking is $51
The total paid WITHOUT the parking is $51-$6 = $45
They spent $3.5(x) for the entry, they also spent $5.5(x) for the pass:
3.5(x) + 5.5(x) = 45
9x = 45 and x = 5 people

11) Translate English to Math language:
Let x be this number:
5.x - 18 - 4.x = -36

x - 18 = -36 Add 18 to both sides
x - 18 + 18 = - 36 + 18
x = - 18