Question

the average of 11 number 10.9 if the average of first six is 10.5 and that of last six is 11.4 then find the sixth no

Answer 1

Answer:

SIXTH NUMBER IS 11.5

Step-by-step explanation:

$sum \: of \: all \: numbers = 10.9 \times 11 . \\ \\ sum \: of \:first\: six\: numbers = 10.5 \times 6. \\ \\ sum \: of \:last\: six\: numbers = 11.4 \times 6. \\ \\ then \: \: \: 10.9 \times 11 - 10.5 \times 6 = 11.4 \times 6 - f \\ \\ 119.9 - 63 = 68.4 - f \\ \\ 119.9 = 131.4 - f \\ \\ f = 11.5$