The average of 25 numbers is 150. One more number is added and the new average became 160. What is that new number?

a) 400
b) 410
c) 415
d) 420

Ans : b) 410

SSC constable GD Paper 204 : Elementary Mathematics

Solution :

Total = average x number
Total₂₅ = 25 x150 =3750

New member is added
Members = 25+1 =26
Average = 160
Total₂₆ = 26×160=4160

New Member is Total₂₆ – Total₂₅ = 4160- 3750 =410