Explanation

The question asks to find how many 7's are there that:

• Are not immediately followed by 3.
• Are immediately preceded by 8.

To solve this:

• We need to check each occurrence of 7 and see if it's preceded by 8 and not followed by 3.

Upon checking the series, the relevant occurrences of 7 are:

• 877 (preceded by 8, but not followed by 3)
• 877 (again preceded by 8, not followed by 3)

So, there are 2 such 7's.

Explanation

A heat detector is used for finding fires by detecting significant increases in temperature

Types:

Some heat detectors respond to a rapid temperature increase ("rate-of-rise"),

While others activate when a specific temperature is reached ("fixed temperature"). 

Explanation

Black, as the CO₂ cylinders are typically marked with black.

Carbon dioxide gas cylinders are usually gray

Commonly, a Grey Cylinder is used in the medical field.

Any cylinder should be filled 1/3rd.

Explanation

(School and Students, Library and Books, Garden and Flowers) represent a relationship between a place and its purpose or inhabitants, Whereas "Classroom and Foot" does not have a logical relationship like the others

Explanation

Carbon Dioxide, Water, and Sand are common and effective methods used for extinguishing fires.

There are six types of fires, and different extinguishing materials are used to extinguish them.

The fire types are

1. Class A
2. Class B
3. Class C
4. Class D
5. Class E
6. Class F

Explanation

Explanation

Explanation

Explanation

If you don't wash your body regularly, you can experience unpleasant body odor,

• increased risk of skin infections,
• clogged pores,
• acne flare-ups,
• irritation,
• a build-up of dirt, sweat, and dead skin cells

It can also lead to a condition called "dermatitis neglecta" in extreme cases,

Explanation

The P wave and PR segment is an integral part of an electrocardiogram (ECG).

It represents the electrical depolarization of the atria of the heart.

Typically, a small positive deflection from the isoelectric baseline occurs just before the QRS complex.