A large number of problems in math can be solved by different logical methods or using formulas. Among these, you have to choose the method through which you can arrive easily at the final answer. In some cases, you will come to know how to solve real life problems in Arithmetic with the help of Algebraic methods.
For an example: -
Average value of a variable (mean) = sum of the values of the variable / total number of the values.
X bar = ∑ x / n
Question 1: - A student, by mistake, wrote 64 in place of 46 as a number at the time of finding the average of 10 given numbers and got the average as 50. Find the correct average of the numbers.
Solution: - Analyzing the problem, we get:
Considering 64 in place of 46 as a number, sum of the 10 numbers = 50 x 10 = 500
Leaving the wrong number, sum of the 9 numbers = 500 – 64 = 436
Therefore correct sum of the 10 given numbers = 436 + 46 = 482
Average of the numbers = 482 / 10 = 48.2
Answer: - Correct average of the 10 given numbers = 48.2
Question 2: - If the scores of mathematics of three students in a class are 70, 80 and 95 then what is their average score of marks.
Solution: - Average = ∑ x / n
= (70 + 80 + 95) / 3