1 adult=2
1 child=1
multiply 2*8=16 adult glasses
multiply 1*5=5 child glasses 
in total she needs 21 glasses
hope I was helpful
 
        
             
        
        
        
Answer:
<h2>50</h2>
Step-by-step explanation:
Put h = 7 to the expression 5 · (h + 3):

 
        
             
        
        
        
My guess is that you're doing the Law of Cosines? You have everything you need for that except the angle theta, which is the thing you need to find.  It's set up like this: (8)^2 = (10)^2 + (5)^2 -[2(10)(5)cos A]  I used A instead of theta. Doing that math, you have: 64 = 100 + 25 -[ 100 cos A]; 64 = 125 - 100 cos A;
-61 = - 100 cos A; -61 / -100 = cos A; .61 = cos A. Now use your inverse function on your calculator to find cos^-1(.61) and that equals 52.4