How do you go from 98 to 720 using just one letter?

Replace each alphabet with the number (1-9) to make the below equation correct.

AB * C = DE - F = GH / I

What will be the best approach to finding all the prime numbers less than 75 that leave an odd reminder when we divide them with 5?

Can you think of any three-dimensional shape that comprises of exactly two surfaces?

Can you think of a smallest +ve number such that if we shuffle the digits of the number, the new number becomes double the original number?

A 52% bias toss for head using the 51% tail bias coin was done to obtain a fair result.

Can you find how bias is the floor in this case?

A mules travels the same distance daily.
I noticed that two of his legs travels 10km and the remaining two travels 12km.
Obviously two mules legs cannot be a 2km ahead of the other 2.

The mules is perfectly normal. So how come this be true ?

You have a roll of cloth 1km long. You have a machine which cuts this roll into pieces of 10-meter-long cloth.

How long would it take for the machine to cut the roll if each cut took 4 secs?

Replace the (?) with the correct mathematical signs to make the expression equal to 59.

18 ? 12 ? 4 ? 5 = 59

Using Only Five 5's and any mathematical operator make sum as 37