Question

the mean attendance of a school of first four days was 780​ and for the first five days the mean was 840 . How many were present on friday​

Answer 1

Step-by-step explanation:

mean of 5>mean of 4 by 60

so 60×4=240

total no students =240+840=1080

alternative explanation

mean of 4=780

sum of 4=780×4=3120

mean of 5=840

sum of 5=840×5=4200

sum of 5-sum of 4=4200-3120=1080

hope this helps