Answer:
it is 8
Step-by-step explanation:
Solution :
Let A = Economics, B = Mathematics
n(A) = 311, n(B) = 243, 
a). So, 
= 311 + 243 - 135
= 419
b). n(A only) = 311 - 135
= 176
n(B only) = 243 - 135
= 108
Exactly one of these two courses
= 0.568
c). Neither economics nor mathematics
= 0.162
Answer:
Step-by-step explanation:
I can not see your answers to choose but with this equation for 2 variables, you can replace the values of x and y and see if that is right or not.
For example, to know (-2,5) is a solution, you replace x= -2 and y= 5
into this equation: -3x -y = 6
and you have: -3*(-2) -5 =6
or 6-5 =6, and you find that is impossible, so (-2.5) is not a solution.
Hope you understand it
Answer:
for four copies the cost is $72
Step-by-step explanation:
52 + 5a = 24 + 12a
28 + 5a = 12a
28 = 7a
a = 4
52 + 20 = 72
for four copies the cost is $72
