Answer:
Student A and Student B both answered 2 questions correctly.
See explanation below
Step-by-step explanation:
Note: that answers in the form:

ARE ALL EQUIVALENT.
First of all, 4/5 is equivalent to 0.8 if we do long division.
and 19/20 is 0.95 if we do long division.
Now, <u>Student A:</u>
Both of the fractions are correct and the negative sign is equivalent and makes the answer correct, so both are correct.
For <u>Student B:</u>
Similarly, both answers are correct for this student as well, looking at the equivalence we showed first.
Also, "-" (negative) in front of the parenthesis and inside parenthesis here doesn't matter.
Hence,
Student A and Student B both answered 2 questions correctly.
Answer:
$28.50
Step-by-step explanation:
21 chicken wings= $39.90
1 chicken wing= 39.90÷21= $1.90
15 chicken wings= 15×1.90= $28.50
I'm not sure what your book is saying about the matter but a cell phone is not usually an essential expense. If it is saying it is though, it would be an essential flexible expense.
There are about 28 grams in an ounce so 45/28 is about 1.5