I think it's 20. Sorry if it's wrong
In my opinion i think it’s D.parallelogram
Get the total amount of the 5 tiles and divide it by 5.
nshs = sshs+5
wshs = nshh + 6 = sshs + 11
So nshs + wshs + sshs = 3*sshs + 16
So sshs = 10, nshs = 15 and wshs = 21
Answer 15.
The easiest way to solve this is by elimination.
3x - y = 6
6x + y = 21
Since you have a negative and positive y with the same coefficients (1), they cancel, and you add the other terms so it would look like:
9x = 27
Then solving for x leaves you with x = 3
Then you take the x value of three and plug it into to either of the equations, so
3(3) - y = 6
9 - y = 6
subtracting 9
-y = -3
then dividing by -1
y = 3
so the solution is x = 3 y = 3 or (3,3)
