Can you decipher the following common phrase?

T M C
A U O
H S M
W T E

In Greek mythology, the Sphinx sat outside of Thebes and asked this riddle of all travellers who passed by. If the traveller failed to solve the riddle, then the Sphinx killed him/her. And if the traveller answered the riddle correctly, then the Sphinx would destroy herself. The riddle:

What goes on four legs in the morning, on two legs at noon, and on three legs in the evening?

Oedipus solved the riddle, and the Sphinx destroyed herself.

You have a three-gallon and a five-gallon measuring device. You wish to measure out four gallons.

What three numbers, none of which is zero, give the same result whether they’re added or multiplied?

Decode below rebus
D
N
A
T
S , D

John drives to his office at 20km/hr. After reaching the office, he realizes that today is a holiday. He went back at an average speed of 30km/hr. Discounting the time spent in the stoppage what was the average speed of his journey?

There are nine letters in the below-given diagram. You have to form a nine-letter word using these letters.

You walk into a room that contains a match, a kerosene lamp, a candle and a fireplace. What would you light first?

If I remove one from eleven it becomes Ten and if I remove one from nine also becomes Ten. How?

I went to the bookshop and spent one-half of the money that was in my purse.

When I came out, I found that I had as many cents as I had dollars and half as many dollars as I had cents when I went in. Find the money in my purse when I entered the store.