Riddles of Im clean when you wash me and dirty when you're not

Alice came across a lion and a unicorn in a forest of forgetfulness. Those two are strange beings. The lion lies every Monday, Tuesday and Wednesday and the other days he speaks the truth. The unicorn lies on Thursdays, Fridays and Saturdays, however the other days of the week he speaks the truth.
Lion said: Yesterday I was lying and two days after tomorrow I will be lying again.
Which day did he say that?

Answer

This conjunction is true only if both parts are true. The first part is true only on Thursday, but the second part is a lie then (Sunday is not a lying day of the Lion). So the whole statement can never be true (at least one part is not true). Therefore the Lion could have made the statement on Monday, on Tuesday and even on Wednesday.

Without fingers, I point,
without arms, I strike,
without feet, I run.

What am I?

Answer

A clock.

Which word, if pronounced right, is wrong, but if pronounced wrong is right?

Answer

Wrong.

77x = 189x = 345x
¿Which is the x value?

Answer

0 (Zero)

I have many teeth but I can’t bite. I’m often used early but rarely at night.
What am I?

Answer

A comb.

In Miss Miranda's class are eleven children. Miss Miranda has a bowl with eleven apples. Miss Miranda wants to divide the eleven apples among the children of her class, in such a way that each child in the end has an apple, but one apple still remains in the bowl.
Can you help Miss Miranda?

Answer

Ten children get a single apple, and the eleventh gets the bowl with an apple still in it.

Invisible until you spy me, I'm or mostly two but never three.
What am I?

Answer

Own eyes.

I am four times as old as my daughter. In 20 years time I shall be twice as old as her.
How old are we now?

Answer

I am 40 and my daughter is 10.

A skin have I, more eyes than one.I can be very nice when I am done.
What am I?

Answer

Potato.

I end and begin the day,
Without me, you'll pay.
With the aid of sheep,
All my benefits you shall reap.
If I make you miss class,
You shall not pass!
What am I?

Answer

Sleep.

Shot two arrows at its center and missed both times, swung a sword once at its center and hit twice.
What is it?

Answer

Any object with a hole in the center, including a doughnut, a bagel, a ring, or a tire.

Since these have holes in the center, shooting arrows at the center would hit nothing, but swinging a sword would hit it twice.

I get sharper the more I’m used.
What am I?

Answer

A brain.