Question

pls friends answer fast but correctly.
1.The arithmetic mean of a series of 20 items was calculated as 20.While calculating it,an item 13 was measured as 30.The correct arithmetic mean is
a)20.5 b)20.15 c)19.25 d)19.15

2.The mean weight of all girls of a class is 36 kg and that of the boys of the class is 42 kg.The mean weight of all students of the class is 40kg .what is the ratio of the no. of girls and boys in the class?
1)1:2 2)1:4 3)2:3 4)3:4

3)what is the mean of the given frequency distribution?
a)21.04 b)23.08 c)25.40 d)27.60

4)Rahul calculated the mean of nine positive integers to be 70.While he was rechecking the answer ,he found that he had written 73 as 37,210 as 102 ,and 35 as 53 by mistake. what is the correct mean of the integers?
1)56 2)62 3)74 4)84

Answer 1

answer for the questions

1.  d)19.15
2.  1)1:2 
4.  4)84