Std-10 Most Imp Ch 8 Gseb L-9

In a Std. X class, out of 40 students, 10 students use spectacles, 2 students have positive power and 8 students have negative power and 8 students have negative power of lenses in their spectacles . Generally which type of spectacles do most of the students use ?

30 16 10 8 8 9 ?

Sum of n terms of the series 8 + 88 + 888 + .... equals (a) 8/81 [10^(n+1) - 9n - 10] (b) 8/81[10^n - 9n -10] (c) 8/81[10^(n+1) - 9n + 10] (d)none of these

{:("Marks (obtained out of 10)", 4,5,7,8,9,10),("Frequency",5,10,8,6,12,9):} The frequency of more than 8 marks is 21.

{:("Marks (obtained out of 10)", 4,5,7,8,9,10),("Frequency",5,10,8,6,12,9):} The frequency of less than 8 marks is 29. ??

List two most common STDs.

Most common bacterial STD is:

Let A = {7, 8, 9, 10} and R = {(8, 8), (9, 9), (10, 10), (7, 8)} be a relation on A, then R is