Answer:
The required expression is
.
The value of the expression when y=20 is 2.
Step-by-step explanation:
Consider the provided phase.
3 less than the quotient of a number y and 4
The quotient of a number y and 4 can be written as: 
Now 3 less than the quotient of a number y and 4 can be written as:

Hence, the required expression is
.
Now evaluate when y=20.
Substitute y=20 in above expression.



Hence, the value of the expression when y=20 is 2.
10.5+(10.5*.4)=10.5+(4.2)=14.7lbs after the first month
42-14= 28
28÷2=14
answer: there are 14 females in the class and 28 males in the class
Check:14+28=42