The first step to solve this problem is to compute for the total money of Veronica. You can do this by:
$35 (given to bill) / 20% (percentage of her money given to Bill) = $175
Since you already know the total money of Veronica, you can now compute how much she spent to buy books which are 50% of her remaining money after giving Bill $35.
($175 - $35) x 50% = $70
Therefore, she spent $70 for her books.
$175 – $35 – $70 = $70
Therefore, she has $70 left.
tbh google