SSC CHSL 7 Mar 2018 Shift 2 Paper

Average of 31 numbers = 19
⇒ Sum of 31 numbers = 19 × 31 = 589
Average of first 8 numbers = 24
⇒ Sum of first 8 numbers = 24 × 8 = 192
Thus, sum of remaining (31-8) 23 numbers = 589 − 192 = 397∴ Required average = 397/23 =17.26