 Hello and welcome to the session. Let us discuss the following question. Question says the following table gives the literacy rate of 35 cities find the mean literacy rate. This is the given table. First of all let us understand that mean is equal to summation f i x i upon summation f i where x bar is the mean, f i is the frequency, x i is midpoint of the interval or we can say class mark of the interval. This method of finding the mean is known as direct method. Now we will use this method as our key idea to solve the given question. Let us now start with the solution. First of all let us rewrite the data given in the question. We are given literacy rate in percentage and number of cities. Now let us find out midpoint of every class interval or we can say we will find out class mark of every class interval. Now we know class mark is equal to upper class limit plus lower class limit upon 2. So 55 plus 45 upon 2 is equal to 50. So we will write here 50. Similarly 55 plus 65 upon 2 is equal to 60. Here midpoint of this interval is equal to 70, midpoint of this interval is equal to 80 and here 85 plus 95 upon 2 is equal to 90 or we can say midpoint of this interval is equal to 90. Now we know number of cities represent the frequency. So we will denote it by f i. Now let us find out the product f i x i 3 multiplied by 50 is equal to 150, 10 multiplied by 60 is equal to 600, 11 multiplied by 70 is equal to 770, 8 multiplied by 80 is equal to 640 and 3 multiplied by 90 is equal to 270. Now let us calculate summation f i x i. We know summation f i x i is equal to sum of all these products and sum of all these products is equal to 2430. Now we know sum of all these frequencies is equal to 35 and sum of all these frequencies represent summation f i. So we can write summation f i is equal to 35. Let us now find the mean by using these two values. From key idea we know mean is equal to summation f i x i upon summation f i. Now here x bar represents the mean. So mean is equal to 2430 upon 35. We had substituted corresponding values of summation f i x i and summation f i in this formula and we get mean is equal to 2430 upon 35. Now solving it further we get mean is equal to 486 upon 7. Now this is further equal to 69.43. So we get mean is equal to 69.43 or we can say the mean literacy rate is equal to 69.43 percent. This is our required answer. This completes the session. Hope you understood the solution. Take care and have a nice day.