I'll do a similar problem, and I challenge you to do this using similar techniques!
If John works for 15$ a hour with his friends rather than working for 20$ an hour for 50 hours a month, what's the monthly opportunity cost?
John would make 20*50=1000 dollars a month at the second option as he makes 20$ an hour 50 times. Next, if he works with his friends, he makes 15*50=750 dollars as he works 50 hours for 15 dollars an hour, or adds 15 50 times.
His opportunity cost would be <highest money>-<lowest money>=1000-750=250 dollars a month. Good luck on this question, and feel free to ask further questions!
Answer:
D 9m 4m because 9 divided by 2 is 3 and 4 divided by 2 is 2 and that's us you answer.
63/84 divided by 21/21
=3/4
or
63 divided by 84=0.75 which is the same thing as 3/4
X + y = 40.....multiply by -4
4x + 6y = 180
-------------------
-4x - 4y = -160 (result of multiplying by -4)
4x + 6y = 180
------------------add
2y = 20
y = 20/2
y = 10 <===
x = 30
Answer:
The choice Draw 2
Step-by-step explanation:

I hope I helped you^_^