Question

The average height of 10 students is computed as 153cm. But it was revealed later the height of one student which was 151cm, was wrongly read as 141cm. The correct average height is ?

Answer 1

Answer:

10*151=1510+10=1520

1520/10=152 ans

Answer 2

Mean = sum of obs./no. Of obs. Given : 153 cm = sum of obs / 10 , or mean height of 10 students is 153 cm. So, sum of obs = mean × no. Of obs= 153×10= 1530 cm. Now , subtract 141 cm from sum of obs.= 1530-141= 1389cm .As 141 was added by mistake. Now , add 151 cm to 1389cm as it was supposed to be done. So, correct sum = 1389+151 = 1540 cm. So, correct mean = correct sum / no. Of obs. = 1540/10= 154 cm ( Answer)