Explanation

Provisional security refers to local or regional security arrangements, typically handled by the District Police.

Customs deals with border control and goods regulation.

Explanation

The idiom means accepting a task that is too difficult or too much to handle.

It suggests overestimating one's ability or time.

Explanation

The subject "dog" is singular and the action is habitual (every day).

For singular subjects in present tense, we use verb + s → barks.

Explanation

Given data:

The seller sells 40% of his apples.
After selling, he still has 420 apples.
Concept/Formula:

The concept used to solve this problem is related to "percentage". The seller was left with 60% of his apples (100% - 40% = 60%) when he had 420 apples left.

Solution:

⇒ the 420 apples represent 60% of his original stock (since he sold 40%).

⇒ If 60% of the original stock equals 420 apples, then 1% can be calculated by dividing 420 by 60.

Hence, 1% = 420 ÷ 60 = 7 apples.

⇒ Now, to find the total original stock (100%), the amount per 1% is multiplied by 100.

Therefore, the original amount = 7 × 100 = 700 apples.

Therefore, originally, he had 700 apples.

Explanation

Given x + 1/x = 10:

Step 1: Square both sides

(x + 1/x)² = 10²

x² + 2(x)(1/x) + 1/x² = 100

x² + 2 + 1/x² = 100

Step 2: Solve for x² + 1/x²

x² + 1/x² = 100 - 2

x² + 1/x² = 98

Explanation

Subtracting a negative is the same as adding: (-0.9) - (-0.9) = -0.9 + 0.9.

The result is 0.