Question

The mean of a set of seven numbers is 81. If one of the numbers is discarded,the mean of the remaining numbers is 78. The value of discarded number is

Answer 1

$81 = \frac{x1 + x2 + x3 + x4 + x5 + x6 + x7}{7} \\ x 1+ x2 + x3 + x4 + x5 + x6 + x7 = 567 \\ let \: x 7\: be \: discarded \\ \frac{x1 + x2 + x 3+x4 + x5 + x6 }{6} = 78 \\ x1 + x2 + x3 + x4 + x5 + x6 = 468 \\ x7 = 567 - 468 = 99$

Answer 2

Answer:

Step-by-step explanation: