Respuesta :
Answer:
The first one does NOT apply: $9.75 / 5 = $1.95
The second one does apply: $280 / 8 = $35 and $350 / 10 = $35
The third one does apply: $140 / 10 = $14 and $168 / 12 = $14
The fourth one does apply: $12.50 / 10 = $1.25 and $8.75 / 7 = $1.25
The fifth one does NOT apply: 60 / 5 = 12
Hope this helps!
Rate is the measure of increment in number of dependent quantity per unit independent quantity. The situations having correct unit rate are:
- Case 2: John earning from mowing lawns
- Case 3: Kayla paying for yoga classes
- Case 4: Keisha buying cups of coffee.
What is unit rate?
There is independent quantity, and a quantity which depends on it (dependent quantity). When independent quantity moves by a unit measurement (single unit increment), the increment in dependent quantity is called rate of increment of dependent quantity per unit increment in independent quantity.
For the given cases, we have:
- Case 1: Sara pays $9.75 for 5 cupcakes.
It means
[tex]5 \: \rm cupcakes = \$9.75\\\text{Dividing both the quantities by 5}\\\\1 \: cupcake = \$9.75/5 = \$1.95[/tex]
(we equated both quantities on deal level(deal is made by thinking that 5 cupcake will be equal to $9.75))
The rate of price (dependent quantity) of 1 cupcake(quantity of cupcake is independent quantity as it comes first, without any effect of price(assuming)) is $1.95, and not $1.75
Thus, the rate given is wrong in this case.
- Case 2: John earns $280 for moving 8 lawns
It means
[tex]\$280 \: \rm earned = 8 \: lawns \: mowed\\\\\\\text{Dividing both quantities in 8 parts}\\\\\dfrac{280}{8} = \$35 = 1 \: lawn \: mowed[/tex]
Thus, mowing 1 lawn will make John earn $35.
For 10 such mowing, he will get $35 + $35 .. + 35 (10 times) = 35×10 = $350
Thus, as it is given that "At the same rate he will earn $350 for mowing 10 lawns", thus, thus case is correctly using rate of amount earned per unit lawn mowed.
Similarly,
- Case 3:
$140 = 10 yoga classes
Dividing in 10 parts
$14 = 1 yoga class
(rate is $14 per unit (single) yoga class)
Multiplying with 12, we get:
$168 = 12 yoga classes.
Thus, its equal to given quantity and thus, this case is correctly using the unit rate,
- Case 4:
$12.50 = 10 cups,
$1.25 = 1 cup
For 7 cups, Multiply with 7,
$8.75 = 7 cups,
Thus, given rate $8.75 per 7 cup is correct.
- Case 5:
60 miles = 5 days
12 miles = 1 day
So unit rate is 12 miles each day and not 14 miles each day. So this case calculates wrong unit rate.
Thus,
The situations having correct unit rate are:
- Case 2: John earning from mowing lawns
- Case 3: Kayla paying for yoga classes
- Case 4: Keisha buying cups of coffee.
Learn more about rate of change here:
https://brainly.com/question/11484885
