Question

The scores of 19 students averaged 80. If the score of the 20th student is counted, average score is 82. What is the score of the last student?

Answer 1

✪ Answer : 120

✪ Step-by-step explanation :

✍️ Since we know that,

Average = Mean of observation

Mean = ∑( 1/n )

80 = ∑ × 1/19

80 × 19 = ∑

1520 = ∑

✍️ When there are 20 students instead of 19,

82 = ∑'( 1/20 )

82 × 20 = ∑'

1640 = ∑'

✍️ Now when x20 is added in value of ∑ then it becomes ∑'

∑' = ∑ + x20

1640 = 1520 + x20

1640 - 1520 = x20

120 = x20

✪ Score of 20 th student is 120.