# Answer

1)Average cost of 10 fans equals 1440

2) 2

# Steps

1)524/262

(2X262)/(2X131)

2 gets cancelled

(262)/(131)

(2X131)/(131)

131 gets cancelled

Equals 2

# Steps

4 fans@ 1200 is 4800

6 fans @ 1600 is 9600

Hence 10 fans is (4800 plus

9600) equals 14400.

Hence average cost

14400/10

Equals 1440