Explanation

The drum of a Photostat machine (also known as a xerox machine) is made of a material called selenium,

That is a photoconductive element.

This means that when exposed to light

It becomes conductive, allowing the machine to transfer the image onto the paper. 

Explanation

This sentence is an indirect question, which is a polite way to ask for information.

In the indirect question, we do not invert the subject and verb as we do in direct questions.

Instead, the subject ("the cinema") comes before the verb ("is"), maintaining the normal subject-verb order of a declarative sentence.

Therefore, the correct choice is:  The cinema is

Explanation

There were a few people in the mall, so we weren’t completely alone.

“A few” is used for a small number of countable nouns like “people”.

Explanation

The mesosphere is the coldest layer of the atmosphere, with temperatures dropping as low as -90°C.

It lies above the stratosphere and below the thermosphere.

Explanation

If 15 men can complete the work in 12 days,

it means that the total number of man-days required to complete the work is:

15 men * 12 days = 180 man-days.

180 man-days / 9 men = 20 days.

Explanation

Hippocrates was a Greek physician.

Hippocrates is called the "Father of Modern Medicine" for his systematic approach to clinical medicine.

He emphasized observation, diagnosis, and ethics, laying the foundation for modern medical practice.

Explanation

Operation Radd-ul-Fasaad Launched on February 22, 2017.

The intensive nationwide operation against terror groups, steered

by Army Chief General Qamar Javid Bajwa

******

Operation Zarb-e-Azb started by Army Staff General Raheel Sharif.

Operation Zarb-e-Azb start from 15 June 2014 till 22 February 2017.

Explanation

To solve this problem, we can use the concept of man-days:

8 people × 60 days = 480 man-days

Since the amount of work remains the same, we can set up an equation for 6 people:

6 people × x days = 480 man-days

To find the number of days, divide 480 by 6:

x = 480 ÷ 6

x = 80 days

Explanation

Man climbs 20 yards and slips down 5 yards in one minute

i.e. he climbs (20-5 = 15 yards) in one minute.

But in the last minute, he will be climbing 20 yards as he gets on the top so no slip.

Time taken to climb 80 yards = 60/15 + 1

                                                   = 5 minutes.

He climbs the hill in 5 minutes

Explanation

Salt and water can be recovered from an aqueous salt solution by the process of evaporation.