DrH = DrT + 0.019
DrE = DrH - 0.020
DrH is the most and DrE is the least
For this case we propose a system of equations:
x: Let the variable representing the number of children in the concert
y: Let the variable representing the number of adults at the concert
According to the assistance we have:

According to the cost we have:

Substituting the first in the second equation we have:

Thus, the concert was 375 adults.
On the other hand we have:

Thus, the concert was 1125 children.
In total they were:
people
ANswer:
The concert was 1500 people
Using the quadratic formula, the answers could be A B and D
Step-by-step explanation:
Total amount of apples in one bag:

Hence, total amount of apples in two bags:

or

or

Hence, B, D and E are correct.
A is incorrect because you are adding 2 more apples on top of the total amount of apples in one bag, and you cannot assume that there are 2 apples in each bag.
C is incorrect because you are multiplying the apples together, but you are supposed to add them up to find the total.
F is incorrect because you are finding 1/2 a bag.