Question

If x + y = 6, y + z = 7, and z + x = 9, the average (arithmetic mean) of x, y and z is:
(A) 11/3
(B) 11/2
(C) 22/3
(D) 11​

Answer 1

Answer:

Answer is (A) = 11/3

Steps

x+y=6..........Equation No.1

y+z=7

z+x=9

then. z=7-y , z=9-x

therefore 7-y = 9-x

x-y= 9-7=2.......Equation No.2

so

x+y = 6

x-y =2

2y = 4

y=4/2

y=2

therefore x+y=6 , y=2

x+2=6

x=6-2=4

x=4

Remaining y+z=7 , y=2

2+z=7

z=7-2

z=5

AVERAGE = (x+y+z)÷3

=(2+4+5)÷3

=11÷3

AVERAGE=11/3