If AM of a, `a+3, a+6, a+9` and `a+12` is 10, then a is equal to

If A = {1,2,3,4,5,6,7} and B = {7,8,9,10} , then A-B equals :

1, 3, 3, 6, 7, 9, …. 12, 21.

n AM's are inserted between 2 and 38 .If third AM is 14 then n is equal to (A) 9 (B) 7 (C) 8 (D) 10

If '15 + 10 means 5', ' 6 xx 3 means 9' , ' 8 div 4 means 32 , and ' 12 - 2 means 6' , then what will be the value of 27 + 81 - 9 xx 6 ?

If the mean and variance of the following data: 6, 10, 7, 13, a, 12, b, 12 are 9 and (37)/(4) respectively, then (a-b)^(2) is equal to

If the AM of two numbers is 9 and their HM is 4, then their GM is 6. [True/False]

If the AM and HM of two numbers are 27 and 12 respectively, then what is their GM equal to ?

0, 4, 6, 3, 7, 9, 6, …., 12.