Step 1 :First, we need to calculate the total amount Thor spent on magazines and phones. He bought 4 magazines at $45 each, and 3 phones at $20 each. So, the total amount spent is \(4 \times 45 + 3 \times 20 = 240\) dollars.
Step 2 :Then, we need to subtract the amount he found and the amount he got back from returning the magazines. He found two ten dollar bills, so he found \(2 \times 10 = 20\) dollars.
Step 3 :He returned 3 magazines at $45 each, so he got back \(3 \times 45 = 135\) dollars.
Step 4 :Finally, we subtract the amount he found and the amount he got back from the total amount spent. So, the total change to Thor's funds is \(240 - 20 - 135 = 85\) dollars.