The mean of 31 results is 60. If the mean of the first 16 results is 58 and that of the last 16 results is 62,
Question:
The mean of 31 results is 60. If the mean of the first 16 results is 58 and that of the last 16 results is 62, find the 16th result.
Solution:
Mean of 31 results = 60
Sum of 31 results $=31 \times 60=1860$
Mean of the first 16 results $=58$
Sum of the first 16 results $=58 \times 16=928$
Mean of the last 16 results = 62
Sum of the last 16 results $=62 \times 16=992$
Value of the 16th result $=$ (Sum of the first 16 results $+$ Sum of the last 16 results) $-$ Sum of 31 results
$=(928+992)-1860$
$=1920-1860$
$=60$