Question

The average of 10 items is 77 .the number64 was incorrectlywritten as46 while calculating.find the correctaverage

Answer 1

Answer:

The average of correct numbers is 78.8

Step-by-step explanation:

Given as :

The average of 10 items = 77

i.e $\dfrac{x_1+x_2+x_3+..........x_10}{10}$  = 77

The incorrect number is 46

or, The average = $\dfrac{x_1+x_2+x_3+....46...+x_10}{10}$  = 77

Or, ${x_1+x_2+x_3+....46....+x_10}$ = 77 × 10

Or, $x_1+x_2+x_3 +......x_9$ = 770 - 46

Or, $x_1+x_2+x_3 +......x_9$ = 724

Again

The correct number is 64

So, The average of correct numbers = $\dfrac{x_1+x_2+x_3+.....64...+x_10}{10}$

Or,  The average of correct numbers = $\dfrac{x_1+x_2+x_3+.....+x_9 + 64}{10}$

Or,  The average of correct numbers = $\dfrac{724+64}{10}$

Or,  The average of correct numbers = $\dfrac{788}{10}$

∴  The average of correct numbers = 78.8

Hence,  The average of correct numbers is 78.8 Answer