The product of two positive numbers is 11520 and their quotient is $$9\over5$$.Find the difference of two numbers?

For what value of m will the system of equations 17x+my+102=0 and 23x+299y+138=0 have infinite number of solutions? 

The least value of n, such that (1 + 3 + 3² + ... + 3ⁿ) exceeds 2000, is-

What is the sum of all natural numbers between 100 and 400 which are divisible by 13? 

How may digit are required to write numbers from 1 to 50?

The number of integers in between 100 and 600, which are divisible by 4 and 6 both, is: 

Four numbers, when arranged in ascending order, are w, x, y and z. The average of the smallest three numbers is 25.5 while the average of the largest three was 29.5. What is the range of the data?

The greatest number less than 1500, which is divisible by both 16 and 18, is: