Imagine the letters(symbols) below to sit on scales.

Scale 1 and 2 are perfectly balanced.

Take D = diamonds H = Heart S = spades.

How many diamonds are needed to balance scale 3?

1. D H ........ S S S S

2. S S D D H ........ H H

3. H S S ........ ?

I get the same answer using both logic and algebra, yet it conflicts with the answer I have been given for this.

Please try!