Solution:

painless operation

Solution:

Error

Solution:

Mountain (Mount 10).

Solution:

720

(0!+0!+0!+0!+0!+0!)!
=(1+1+1+1+1+1)!
=(5)!
=6! is 6*5*4*3*2*1=720

Solution:

5

23-2=21
21+3=24
24-5=19
19+7=26
26-11=15
15+13=28
28-17=11
11+19=30
30-23=7
7+29=36
36-31=5


(2,3,5,7,11,13,17,19,23,29,31,37,41,43... are Prime Numbers)

Solution:

36 meters.

100/v1 = 80/v2
100/v2 = 80/v3

20+(20/v2)*v3=20+16 = 36

Solution:

24

write the numbers in ascending order in words as
onE (Position of 'E' in alphabet is 5)
twO (Position of 'O' in alphabet is 15)
threE (Position of 'E' in alphabet is 5)
fouR (Position of 'R' in alphabet is 18)
and so one

Solution:

PACK MY BOX WITH FIVE DOZEN LIQUOR JUGS.

Solution:

20(Twenty) : when you write them , these are only numbers having vowel 'E'

Solution:

I am 72 years old.

Let m be my age in years. If s is my son's age in years, then my son is 52s weeks old. If g is my grandson's age in years, then my grandson is 365g days old. Thus,
365g = 52s.
Since my grandson is 12g months old,
12g = m.
Since my grandson, my son and I together are 120 years,
g + s + m = 120.
The above system of 3 equations in 3 unknowns (g, s and m) can be solved as follows.
m / 12 + 365 m / (52 x 12) + m = 120 or
52 m + 365 m + 624 m = 624 x 120 or
m = 624 x 120 / 1041 = 72.
So, I am 72 years old.