World War 1 riddle

A grandfather is telling his grandson war stories.

"At the end of World War 1, I was awarded for my bravery
after saving a group of my men," the grandfather says.

"You see, we were fighting in northern France and one of our
enemies threw a grenade at us. I managed to pick it up and
throw it away before it exploded. So right after the war
ended, a General gave me a sword, engraved with the words
'Awarded for Bravery and Valor, A True Hero, World War 1'".

"The grandson thinks about the story for a minute and then
says "Grandpa, that story can't be true!"

How did the grandson know?

An Unusual Paragraph

This is a most unusual paragraph. How quickly can you find
out what is so unusual about it? It looks so ordinary, you'd
think nothing was wrong with it. Actually, nothing is wrong
with it. But it is not as ordinary as you might think.
If you think about it for a bit, you will find out why it
is truly so unusual. So what is it? What is so unusual about
this paragraph?

Millionaire and Hats

A millionaire bought a job lot of hats 1/4 of which were brown.
He sold 2/3 of the hats including 4/5 of the brown hats.
What fraction of the unsold hats were brown.

Hourglass Puzzle

You have 2 hourglasses, a 7 minute hourglass and an 11 minute
hourglass, what is the quickest way to time the boiling of
an egg for 15 mins?