If 21x = 79x, what is the value of x?

Can you make numbers like 24, using numbers 3,3,7 & 7 with any arithmetic operator?

The square root of number 121 is "11". What is the square root of the number "12345678987654321."?

A girl is twice as old as her brother and half as old as her father. In 50 years, her brother will be half as old as his father. How old is the daughter now?

Find three whole, positive numbers that have the same answer when multiplied together as when added together.

In a competitive exam, each correct answer could win you 10 points and each wrong answer could lose you 5 points. You sat in the exam and answered all the 20 questions, which were given in the exam.
When you checked the result, you scored 125 marks on the test.

Can you calculate how many answers given by you were wrong?

There is a box. The area of its top is 240 square units, the area of the front is 300 square units and the area of the end is 180 square units.

Can you calculate the dimensions of this box with the given data?

A number can be multiplied by multiple of nine
i.e 9 18 27 36 45 ...

and the resulting number consist of only one digit.

Can you identify the number ?

Baseball bat and ball cost $100. If the bat cost $99 more than the ball, what is the cost of each?

Can you find the largest Three-digit number whose sum is 14 and whose square is less than 5,00,000?