What begins with T, ends with T, and has T in it?

There is a shop where written:
Buy 1 for $1
10 for $2
100 for $3
I needed 999 and still only paid $3. How could this be financially viable for the shop-keeper?

You have to put a letter on the following to make it a meaningful word. The only challenge is that you can't use 'E'.

S E Q U E N C _

I know a 5-digit number having a property that With a 1 after it, it is three times as large as it would be with a one before it.

Guess the number?

Place the numbers from 1 to 9 in the circles in a manner that each side of the triangle sums up to 17.

Christina, Allison and Lena are 3 daughters of John a well-known Mathematician, When I asked John the age of their daughters. He replied "The current age of her daughters is prime. Also, the difference between their ages is also prime."

How old are the daughters?

When my father was 31 I was 8. Now he is twice as old as me. How old am I?

Spelt forwards I’m what you do every day, spelled backwards I’m something you hate. What am I?

What kind of band never plays music?

First, think of the colour of clouds. Next think the colour of snow. Last, think of the colour of the moon. Now, what do cows drink?