Explanation:
First problem looks right. Although he started with 145, not 25. Savings and checking combined is the total amount of cash he had before he started working, which is why it's added to the total amount of money he has.
He saves 55 every week. because the multiplier on w, which is weeks is 55. So for every week 55 is added to the multiplication. Ex 2 weeks is 110, 3 is 165, 4 is 220 etc..
He wanted a total of 650 usd. Doesn't matter where it is the total is what matters. Doesn't matetr if hes spending, storing or even burning the money..
So first make 55w+145=650 then solve
Minus 145 from both sides
55w = 505
About 9 weeks one day and 6 hours. This is a rough estimate since the answer is 9.18181818 weeks.