Final answer:
Jacob should give May $9, which is the price of one pair ($30) minus the amount May paid for her 35% share of the two pairs ($21).
Step-by-step explanation:
The question presented is a mathematics problem that can be solved by calculating the percentage of the total cost. May bought 3 pairs of jeans for $90, which means each pair costs $30 since 90 / 3 = 30. She gives one pair to Jacob and pays 35% of the total cost of the jeans. The 35% she pays is for the two pairs she keeps.
Therefore, we calculate 35% of $60 (the price of two pairs), which is $60 * 35% = $21. So, May pays $21 towards the cost of the jeans.
To find how much Jacob should give May, we assume Jacob pays for the pair he received. Since May already paid $21, and the total cost is $90, the amount Jacob needs to give May is the cost of one pair subtracted from what May has already paid.
Hence, Jacob should give May $30 - $21 = $9.