1) Looking at the first table, we can see that this is a proportional relationship given by y=8.5x
So Anna charges:
Number of hours (x) | Amount (y)
1 8.5
2 17
5 42.5
8 68
11 93.5
a) The expression for her earnings in 11 hours:
y=8.5(11) ⇒ y = 68
$68
b) She'll earn $29.75. We can get it by plugging into that formula.
3 1/2 = 3.5
y= 8.5(3.5)
y=29.75
$29.75
c) To know how long, we plug 51 for y. Since x is for hours.
y=8.5x
51=8.5x Divide both sides by 8.5
x=6
She'll take 6 hours to get $51.00 working as a baby sitter.