Question

the two-pan balance below holds some bags on one side and some blocks on the other. the bags are made out of paper so light it doesnt affect the balance. each bag has the same number of blocks inside it. the two sides are balanced, or equal (in weight).
how many blocks are in each bag?

Explanation:

Step1: Count total blocks on left

Count the blue blocks: $9 \times 5 = 45$

Step2: Set up equation for balance

Let $x$ = blocks per bag. $4x = 45$

Step3: Solve for $x$

$x = \frac{45}{4} = 11.25$
Wait, correction: Re-count blue blocks: $8 \times 5 = 40$

Step2 (corrected): Set balance equation

$4x = 40$

Step3 (corrected): Solve for $x$

$x = \frac{40}{4} = 10$

Answer:

10