Final answer:
Initially, Colin had $40. After spending their money, both Ben and Colin had $10 left.
Step-by-step explanation:
To solve this problem, we'll set up two equations based on the given information.
Let x represent the amount of money Colin had at first. Since Ben had 3 times as much money as Colin, Ben had 3x dollars. After spending, Ben has 3x - 110 dollars left, and Colin has x - 30 dollars left. According to the problem, they both have the same amount of money after spending, so we can set up the following equation:
3x - 110 = x - 30
Subtract x from both sides:
2x - 110 = -30
Now, add 110 to both sides to solve for x:
2x = 80
Divide by 2:
x = 40
So, Colin had $40 at first. Using this value, we can find out how much each had left in the end:
Ben had 3x - 110 = 3(40) - 110 = 120 - 110 = $10.
And Colin had x - 30 = 40 - 30 = $10.
Therefore, both had $10 left after spending their money.