Question

The average of 7 numbers be 9. If eighth number be added their average will be increased by 1. Find the added number. ? a) 10 b) 18 c) 19 d) 17

Answer 1

Answer:

17

Step-by-step explanation:

Given ( x1+x2+x3+x4+x5+x6+x7 ) / 7 = 9

( x1+x2+x3+x4+x5+x6+x7 ) = 9 × 7

( x1+x2+x3+x4+x5+x6+x7 ) = 63

Also given that

( x1+x2+x3+x4+x5+x6+x7+x8) / 8 = 10

(63 +x8) /8 = 10

(63 + x8 ) = 10×8

63 + x8 = 80

x8 = 80-63

x8 = 17

Hope the solution is clear...