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

Can you write down eight eights so that they add up to one thousand?

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

which number am I?

A famous swimmer can swim downstream in a lake in exactly 40 minutes with the lake current.
He can swim upstream in that lake in exactly 60 minutes against the lake current.
The length of the lake is 2 km.

How long he can cover the distance of one side at a still lake with no current?

You have $100 with you and you have to buy 100 balls with it. 100 is the exact figure and you can't go below or above the numbers and you have to use the entire $100. If there is no kind of tax applied how many of each of the following balls will you be able to buy:

Green Balls costing $6
Yellow Balls costing $3
Black Balls costing $0.10

Now, how many of each must you buy to fulfil the condition given?

Solve below popular number sequence
314 159 265 358 979 323 846 ?

What number divided by 4 is the same as that number minus 4?

What three numbers, none of which is zero, give the same result whether they’re added or multiplied?

I throw two dice simultaneously.

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

A network of 20 x 10 squares is given to you.

Can you calculate how many unique squares and rectangles can be formed combining two or more individual squares ?