The arithmetic mean of 100 observations is 50. If 10 is added to each observation then what will be the new arithmetic mean?

If the median of observations 12, 1, 8, 54, 61, 28, 45, 35, 21, 17 is M, then what is the value of 2M + 5?

In an enclosure there are crows and cows. If there are 30 heads and 100 legs, what is the ratio of cows to crows?

When the number 12345678910111213 . . . 99100 is divided by 16, what will be the remainder?

What is the median of all possible factors of 120 ?

What is the digit at the 100th place of number (225)⁴⁰ ?