The average of a collection of 20 measurements was calculated to tb 56 cm. But later it was found that a mistake had occurred in one of the measurement which was recorded as 64 cm., but should have been 61 cm. The correct average must be -

The average of 50 numbers is 38. If two numbers, namely 45 and 55 are discarded, the average of the remaining numbers is ?

Average of first five odd multiples of 3 is -

The average marks obtained by 22 candidate in an examination are 45. The average marks of the first 10 candidates is 55 and those of the last eleven is 40. The number of marks obtained by the eleventh candidate is ?

A student finds the average of ten 2 digits numbers. While copying numbers, by mistake, he writes in number with its digits interchanged. As a result his answer is 1.8 less than the correct answer. The difference of digits of the number, in which he made mistake is ?

The average of x numbers is y2 and the average of y numbers is x2. So, the average of all the numbers taken together is :

There are two groups A and B of a class, consisting of 42 and 28 students respectively. If the average weight of group A is 25 kg and that of group B is 40 kg, find the average weight of the whole class.

A library has an average number of 510 visitors on sunday and 240 on other days. The average number of visitors per day in a month of 30 day beginning with sunday is -

The average of n numbers x1, x2.....xn is $$\overline x $$ .Then the value of $$\sum\limits_{i\, = \,1}^n {} \left( {{x_i} - \overline x } \right)$$   is equal to -

A cricketer whose bowling average is 24.85 runs per wickets, takes 5 wickets for 52 runs in next inning and thereby decreases his average by 0.85. The number of wickets taken by him till the last match was :

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