Answer:
I won't be able to solve the entire question but I will give you the formula and show you how to find the answer
4) 1.65x + 1.36y = 118.17 (i)
x + y = 79. (ii)
From the (i) equation you get
1.65x = 118.17 - 1.36y
x = (118.17 - 1.36y)/1.65 (iii)
Substituting the value of (iii) in (ii)
(118.17-1.36y)/1.65 + y = 79
When you solve it you will get the answer
After that find the value of x and y and multiply them by 1.65 and 1.36 respectively.
Then find their difference and see which class sold more and by how much.
Hope this helps you!
