If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

I am a prime number.
The double of myself is equal to the square of me.

which number am I?

A brand new Mobile Phone was on sale at 20% as a promotional offer. By what per cent must the Mobile price be increased to sell it at the original price again?

While house hunting in London, I came across a very good leasehold property Discussing the lease the landlady told me:

'The property was originally on a 99 years lease and two-thirds of the time passed is equal to four-fifths of the time to come. Now work it out for yourself and see how many years are to go!

Find out a multi-digit number that if multiplied by the number 9 or any of its multiplications products (i.e. 18, 27, 36, 45,..) will result in the multiplication factor repeated (n) number of times.

I throw two dice simultaneously.

What is the probability of getting a sum as 9 of the two numbers shown?

How many pluses should we put between the digits of 987654321 to get a total of 99, and where?

Place a mathematical symbol between the numerals 5 and 9 in such a way that the resulting number is greater than 5 but smaller than 9.

Replace the question mark with the correct number in below Picture:

Replace all '*' with digits 1, 2, 3, 4, 5 and 6 to make below statement true.

* *
x *
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* * *