The price of 7 cell phones, 9 TV sets and 12 air-conditioners is $8723;
The price of 5 cell phones, 7 TV sets and 9 air-conditioners is
$6523;
What is the price of 4 cell phones, 4 TV sets and 6 air-
conditioners?

here, 7 cellphone,9 Tv, 12airconditioners = 8723

5 cellphone,7 Tv, 12airconditioners = 6523

or, 7,9,12=8723

-5,7,9=6523

2,2,3=2191

then,

to make 4 cellphone , 4 tv set , 6 air conditioners add twice the answer ,

2,2,3=2191

+2,2,3=2191

4,4,6=4382

hence,

the price of 4 cellphone , 4 tv set and 6 air conditioners is 4382 #

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