Explanation

A probability greater than 0.5 but less than 1 indicates that the event is more likely than not to occur.

A probability of 1 means certainty, so anything between 0.5 and 1 leans toward happening.

Explanation

Calcium carbonate (CaCO₃) is insoluble in water due to its strong ionic lattice and low solubility product.

In contrast, salts like sodium and potassium compounds are generally highly soluble in water.

Explanation

Given tan θ < 0 and cos θ > 0:

Since cos θ > 0, θ lies in either the 1st or 4th quadrant.

Given tan θ < 0, θ lies in either the 2nd or 4th quadrant.

Combining both conditions, θ must lie in the 4th quadrant.

Explanation

To evaluate the expression, we need to find a common denominator. The least common multiple (LCM) of 9, 8, and 3 is 72.

Let's convert each fraction:

7/9 = (7 × 8) / (9 × 8) = 56/72

6/8 = (6 × 9) / (8 × 9) = 54/72

6/3 = (6 × 24) / (3 × 24) = 144/72

Now, add the fractions:

56/72 + 54/72 + 144/72

= (56 + 54 + 144) / 72

= 254/72

Simplify the fraction:

254/72 = 127/36

Explanation

Infra-red waves are electromagnetic waves and do not require a medium to travel.

Mechanical waves like water, sound, and seismic waves need a medium (solid, liquid, or gas) to propagate.

Explanation

Hero's formula (also spelled Heron's) is used to find the area of a triangle when all three sides are known.

Heron's formula:

Area = √(s(s-a)(s-b)(s-c))

where:

- a, b, and c are the lengths of the sides

- s is the semi-perimeter (s = (a+b+c)/2)

Explanation

The hierarchical model organizes data in a tree-like structure, similar to an organizational chart, where each record has a single parent and can have multiple children.

It represents relationships between data in a parent-child hierarchy.

Explanation

A system analyst studies and analyzes business problems and designs efficient information systems to solve them.

They act as a bridge between users and developers, planning solutions and coordinating software/system development.

Explanation

In a periscope, mirrors are placed at 45° angles to reflect light down the tube.

This allows the viewer to see over or around obstacles.

Explanation

The apostrophe (') is mainly used to show possession (e.g., Ali’s book).

It can also show omissions in contractions (e.g., don’t = do not), but in this context, possession is correct.