If the cost of a dozen donuts is $4.80 and a bag of 16 rolls costs $4.80, what
is the cost of 3 donuts and 3 rolls?
(A) $2.40
(B) $0.70
(C) $7.20
(D) $2.10
(E) $9.60

Ok so first, we have to find out how much 1 donut costs. Which is very easy. All we have to do is: 12 which is a dozen divided by $4.80.
12 divided by 4.80 = 2.5
So each donut costs $2.5
Now we have to do the same thing for the rolls, 16 divided by $4.80.
16 divided by 4.80 = $3.33
So each roll costs $3.33.
Now we’ll find the price of 3 donuts:
3 x 2.5 = $7.5 for 3 donuts
Now the price of 3 rolls:
3 x 3.33 = $9.99

Now add the prices:
9.99 + 7.5 = $17. 49

$17.49 is the answer

Each donut is .40 cents each
Each roll is .30 cents each
.40 x 3 = 1.20
.30 x 3 = .90
1.20 + .90 = 2.10
D. Is the answer

If you make it a little more clear i can answer it