Solution:

9 - 8 + 76 - 5 + 4 + 3 + 21 = 100


Other ways of making number 100 (withiout using number 32)
98 + 7 + 6 - 5 - 4 - 3 + 2 - 1 = 100
98 - 7 - 6 - 5 - 4 + 3 + 21 = 100
9 - 8 + 76 - 5 + 4 + 3 + 21 = 100
98 - 7 + 6 + 5 + 4 - 3 - 2 - 1 = 100
98 + 7 - 6 + 5 - 4 + 3 - 2 - 1 = 100
98 + 7 - 6 + 5 - 4 - 3 + 2 + 1 = 100
98 - 7 + 6 + 5 - 4 + 3 - 2 + 1 = 100
98 - 7 + 6 - 5 + 4 + 3 + 2 - 1 = 100
98 + 7 - 6 - 5 + 4 + 3 - 2 + 1 = 100
98 - 7 - 6 + 5 + 4 + 3 + 2 + 1 = 100
9 + 8 + 76 + 5 + 4 - 3 + 2 - 1 = 100
9 + 8 + 76 + 5 - 4 + 3 + 2 + 1 = 100

Solution:

Amin is the terrorist

Explanation:
The message is "tstimeirorwatchretehourhtsisecondsnidialma"

Step1 :
Rewrite the above message as
"ts time iror watch rete hour htsi seconds ni dial m"

Step2:
Now remove all words related to time like (time,watch,hour,seconds,dial) and combine them.
"tsirorretehtsinima"

Step3
Reverse the word.
"tsirorretehtsinima"

Step4.
Add spaces where necessary
"tsirorret eht si nima"

Step5:
Reverse again
"amin is the terrorist"

Solution:

It's shown in the red circle below.

Solution:

Three possible ways are shown in the image below.

Solution:

It can be solved as below.

Solution:

930

Explanation:
New number = Last number * multiplication factor (increased by 0.5 every time) + sum factor (increased by 5 every time)
10
10 * 0.5 + 5 => 10
10 * 1.0 + 10 => 20
20 * 1.5 + 15 => 45
45 * 2.0 + 20 => 110
110 * 2.5 + 25 => 300
300 * 3.0 + 30 => 930 , desired answer

Solution:

It's simple puzzle
Distance = speed * time
= 2meter/seconds * 2 * 50 * 60
= 14400 meteres
= 14.4 kms

My thoughts -
This puzzle reminds us of life when we are stuck at a difficult situation and stop losing hope but if try hard it can be actually a simple problem.

Solution:

Sam : 2
Dean : 5
Castiel : 7

Age diff
7 - 2 = '5' is prime
7 - 5 = '2' is prime
5 - 2 = '3' is prime

Solution:

522

Explanation:
1st Number = Number of alphabtes
2nd Number = Number of vowels
3rd Nummber = Number Of Circles

Lavesh = 6 alphabets + 2 vowels(a,e) + 2 circles(in 'a' and in 'e') = 622
Anmol = 5 alphabets + 2 vowels(a,0) + 2 circles(in 'a' and in 'e') = 522
Shruti = 6 alphabets + 2 vowels(u,i) + 0 circles = 620
Aakriti = 7 alphabets + 4 vowels(a,a,i,i) + 2 circles(in 'A' and in 'a') = 742
Hence,
Sonal = 5 alphabets + 2 vowels(a,o) + 2 circles(in 'a' and in 'o') = 522

Solution:

To add commutative balance in the puzzle above is mistake
You will get this when I show you another way to spend $50.

Spent Balance
5                   45
5                   40
5                   35
5                   30
5                   25
5                   20
5                   15
5                   10
5                   05
5                   00
=========
50                   225

The numbers i choose smartly to confuse readers.