Question

Sasha earns extra money as a babysitter. She earns $37 for 4 hours, and $64.75 for 7 hours. Identify the constant of proportionality, and write an equation for the proportional relationship.

Answer 1

Answer:

Condition 2: $64.75 for 7 hours

So for there to be 1 answer these must have the same ratio as each other. Lets test this:

Both should have the same value if we apply:

$

64.75

$

37

⇔

7

4

1.75

⇔

1.75

The ratios are consistent thus we can calculate unit rate using any one of condition 1 or condition 2. I chose condition 1 as it starts with whole numbers.

Making time become 'unity'

$

37

4

→

earnings for given time

given time is 1 hour (unity)

$

37

4

hours

≡

some value

1

$/h

To change the 4 into 1 we divide by 4. To maintain consistent proportionality what we do to the bottom we do to the top (for multiply or divide).

$

37

4

hours

≡

$

37

÷

4

4

÷

4

=

some value

1

$/h

=

9.25

1

$/h

So the unit rate is $9.25