Find the sum of 2x terms of the series ( 1² - 2² + 3² - 4² + ___ ) 

Find the average of the cubes of the first five natural numbers. 

The smallest positive integer, which when multiplied by 392 gives the product a perfect square number, will be :

Find the greatest value of (a + b) such than an 8-digit number 4523a60 b is divisible by 15.

Directions: Find the wrong number in the following number series:

141, 156, 147, 162, 153, 165, 159

If 30% of a = b, then b% of 50 is the same as:

Find the greatest value of k for which the 6-digit number 24312k is divisible by 6.

If a shopkeeper buys 2 oranges for Rs.5 and sells 3 for Rs.7 only, then what percentage of loss and loss did he gain?