Questions

We can make an equation:

3(100000 + x) = 10x+1

(Why? Well, adding 100000 puts a 1 at the front of a five-digit number, and multiplying by 10 and adding 1 puts a 1 at the end of a number)

Solving this gives:

10x+1 = 3(100000 + x)
10x+1 = 300000 + 3x
10x = 299999 + 3x
7x = 299999
x = 299999/7 = 42857

The answer is 42857 (142857 is three times smaller than 428571).

The logic in the given puzzle is 

4 + 4 = 4 * 4+1 = 4 * 5 = 20

5 + 5 = 5 * 5+1 = 5 * 6 = 30

6 + 6 = 6 * 6+1 = 6 * 7 = 42

7 + 7 = 7 * 7+1 = 7 * 8 = 56

Similarly

9 + 9 = 9 * 9+1 = 9 * 10 = 90.

A Disease which spreads by contact are Contagious.

Infectious diseases : These are caused by microscopic germs such as bacteria or viruses that get into the body and cause problems. Some but not all infectious diseases spread directly from one person to another. Infectious diseases that spread from person to person are said to be contagious. Some infections spread to people from an animal or insect, but are not contagious from another human. 

Contagious diseases such as the flu, colds, or strep throat spread from person to person in several ways. One way is through direct physical contact, like touching or kissing a person who has the infection. Another way is when an infectious microbe travels through the air after someone nearby sneezes or coughs.

Fatal Diseases : Diseases leading to failure or disaster.

Incurable Diseases : Diseases of a sick person not able to be cured.

AOL Time Warner (USA) reported an annual net loss of $98.7 billion on 30 January 2003.