Answer:
He determined pounds per dollar by dividing 10 by 25 but wrote the unit rate as a dollar value.
Step-by-step explanation:
Given



Required
Determine Ming's error
Ming's error is from here

He calculated the unit rate as pound per dollar.
So, after calculating the unit rate, the unit should be:

But instead, he solved as:

<em>Hence, (a) is correct</em>
Answer:
The answer to your question is given below.
Step-by-step explanation:
To know the correct answer to the question, do the following:
√12 + √108
= 12^½ + 108^½
= 4^½ • 3^½ + 36^½ • 3^½
Factorise
3^½ (4^½ + 36^½)
Recall:
4^½ = √4 = 2
36^½ = √36 = 6
Therefore,
3^½ (4^½ + 36^½) = 3^½ (2 + 6)
= 3^½ • 8
$26.79
If you took 30% of 26.79 you get 8.037
Subtract: 26.79-8.037 = 18.753