Question

A mine extracts 2 tons of ore in an hour. Of the total ore extracted in a day, 4 tons is purchased by the government and more than 10 tons is sold to a mineral extractor. If the mine operates for x hours in a day, what is the simplest inequality that represents the number of hours the mine must operate to meet its obligations?

A) x > 2
B) x > 4
C) x > 5
D) x > 7

Answer 1

The answer is D because they must extract 14 tons to meet their obligations. If they extract 2 tons per hour, they must work at least 7 hours.
x>7

Answer 2

Answer: Option 'D' is correct.

Explanation:

Since we have given that

Number of tons of ore a mine extracts in an hour = 2 tones

Let the number of hours in a day the mine operates be 'x'.

Number of tons is purchased by the government = 4 tons

According to question, there is more than 10 tons is sold to a mineral extractor.

So, it becomes,

`2x-4>10\\\\2x>10+4\\\\2x>14\\\\x>(14)/(2)\\\\x>7`

Hence, Option 'D' is correct.