What goes up but never comes down?

A brand new Mobile Phone was on sale at 20% as a promotional offer. By what per cent must the Mobile price be increased to sell it at the original price again?

What is the fastest way to double your money?

Detective John was investigating a murder in China.
It was a difficult case, and John was completely stumped until he noticed a message sent to him by the killer cunningly hidden in a newspaper advertisement selling Car Licence Plates.
Detective John thought about it for a while, and when he had solved the puzzle, immediately arrested the guilty man.

Q1) How did John know the advert was a clue for him?

Q2) Solve the code and tell me who John arrested.

This is the newspaper advert (Car licence plates for sale) that Detective John saw.

Plates For Sale;

[W 05 NWO]
[H 13 HSR]
[O 05 EBM]
[D 08 UNE]
[U 10 HTY]
[N 04 BRE]
[N 16 TTE]
[I 26 LHC]
[T 10 AEE]
[I 26 CNA]
[X 22 VDA]

When 99 is considered higher than 100?

Can you decipher the below rebus?

PBLUESAISNUERSES

I am looking for a word that change both gender and number when i add the letter 'S'.

What Word am I Looking For ?

The following "Brain Bat" means Slow Down.
S
L
O
W

Using the same logic, can you tell us what does the following Brain Bat means ?
E
V
I
G

Chhote se Chintu Miyan,
Lambi si Pooch.
Jahan Jaye Chintu Miyan,
Wahan Jaye Pooch.

छोटे से चींटू मियाँ,
लंबी सी पूंछ।
जहाँ जाये चींटू मियाँ,
वहाँ जाये पूंछ।

Bolo kya?

It belongs to you, but other people use it more than you do. What is it?