Beatrice looked at 3 x 8 TVs at an online store = <<3*8=24>>24 TVs.
She looked at 8 TVs in person + 24 TVs online = <<8+24=32>>32 TVs.
Beatrice looked at 42 TVs in all - the 32 she looked at = <<42-32=10>>10 TVs she looked at on an auction site.
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