The average height of 39 telecom towers which are arranged in an ascending order is 282 m. If the average height of first 19 telecom towers is 280 m and that of last 19 telecom towers is 284 m, then what is the height of 20th telecom tower? (In m)

Correct option is B

Average height of 39 towers = 282 m

Total height of 39 towers
= 39 × 282
= 10998 m

Average of first 19 towers = 280 m
Total = 19 × 280
= 5320 m

Average of last 19 towers = 284 m
Total = 19 × 284
= 5396 m

Height of 20th tower
= 10998 − (5320 + 5396)
= 10998 − 10716
= 282 m