Solution:

There are multiple solutions to the brain teaser.

1) 11+13+3! = 30
2) 11.5+5.5+13 = 30
3) 11+13+6(rotating 9)... my favorite.

Solution:

A - Gold
D - Silver
C - Bronze

Solution:

SHERLOCK

Explanation:
The Number just denotes the position of the letter in the word.
6 Goals Marcos => S
3 Goals Cahil => H
2 Goals Cesar => E
5 Goals Hazard => R
3 Goals Willian => L
8 Goals Jorginho => O
1 Goal Charley => C
4 Goals Barkley => K

Solution:

A Party

Solution:

It can be done as shown below.

Solution:

RS

Explanation:
The list is formed by using last two letter of planet's names in the order from Neptune To Mercury

NEPTU-NE
URAN-US
SATU-RN
JUPIT-ER
MA-RS
EAR-TH
VEN-US
MERCU-RY

Solution:

When blind man "Grandpa" opened his bandages, the train must be passing through the dark tunnel. The man thought he was still blind and hence commit suicide.

Solution:

What is your color

Explanation:

== Step-1 : Write all the colors ==
White White Black White Blue
Silver Pink Blue Blue Blue
Orange Purple Purple Gray Blue
Orange Orange Yellow Black Yellow

== Step-2: select nth letter of, where n is the column number (Note: we will ignore blue ==
w h a t _
s i _ _ _
o u r y _
o r l c o

== Step-3 : Unscramble each row==
what
is
your
color

Solution:

Oscaru and Austin.

Explanation:
The Chemist hide the name using periodic table as shown in below picture
76-20-44 => Os(76) + Ca(20) + Ru(44)
79-16-22-7=> Au(79) + S(16) + Ti(22) + N(7)

Solution:

288/61 hours (4 hours, 43 minutes and 17 seconds approx)

Explanation:
In 1 hour, the ratio of swimming pool filled by pipes:
1st pipe: 1/48
2nd pipe: 1/72
3rd pipe: 1/96
4th pipe: 1/6

All togther
1/48 + 1/72 + 1/96 + 1/6
=> (6+4+3+48) / 288 = 61/288.
=> 288/61 hours,

which is 4 hours 43 minutes and about 17 seconds.