Question

the scale shown can be balanced when both sides have the same number of grams.
which weight can you add to 65 grams to balance the scale?
65 grams + ? = 90 grams
15 grams
25 grams
35 grams
45 grams

Explanation:

Step1: Define unknown weight

Let $x$ = weight to add to 65g.

Step2: Set up balance equation

$65 + x = 90$

Step3: Solve for $x$

$x = 90 - 65$
$x = 25$

Answer:

25 grams