Answer:
25%
Explanation:
To find the percentage discount for the cost of the cell phone, we need to first find the difference between the original price and the discounted price:
$120 - $90 = $30
Then we need to divide this amount by the original price and multiply by 100% to express the result as a percentage:
($30 / $120) * 100% = 25%
Therefore, the percentage discount for the cost of the cell phone is 25%.