What is middle value of a class interval which lies between true upper limit and true lower limit called?

The mid value of a class interval is 42. If the class size is 10 then the upper and lower limits of the class are

Upper limit of class interval 75-85 is

The mid-value of a class interval is 42. If the class size is 10, then the upper and lower limits of the class are: 47 and 37 (b) 37 and 47 37.5 and 47.5 (d) 47.5 and 37.5

The mid value of a class interval in 42 and the class size is 10 then find lower and upper limits.

The monthly salary of some families in a society is given below : (i) What is the lower limit of the second class interval? (ii) What is the upper limit of the last class interval? (iii) What is the class size of each class interval? (iv) What is the mid-value of the third class interval? (v) How many families earn Rs. 50,000 or more in a month? (vi) How many families earn less than Rs. 20,000 in a month?