Given:

He does mistake in the order of giving preference.
We should give preference in the order, division, multiplication, addition, subtraction.
But, he gave the first preferrence to the subtraction.
72-8=64
Next, he used division
64/2=32
Next he adds 32 with 8.
So, he gets 50.
But the actual simplification is,
Simplifying we get,

Hence, the correct value of the expression is 86.
Answer:
12x+4
Step-by-step explanation:
No. This is not random sampling as the students chose are not chosen at random. Random sampling would be something done where each sample has equal probability of being chosen. Clearly this is not random sampling.
Answer:
3x + x + 3x + x = 360
8x = 360
x = 45
3(45)= 135
Step-by-step explanation: