Final answer:
Jake ends up with $55 + $X
Step-by-step explanation:
Jake starts with $100 in his spending money. He spends $15 at Tastee Sub and $10 at Wawa, so he has $100 - $15 - $10 = $75 left. Then he finds a $20 bill, so he now has $75 + $20 = $95. Next, he lends $40 to Brandon, so he now has $95 - $40 = $55. Finally, if Jake earns $X from doing chores, his total amount at the end of the day will be $55 + $X.