Final answer:
Edmond needs to save for approximately 10 weeks, which is equivalent to about 2.5 months, to purchase the computer. The correct equation is 45 + 75x = 768, solved by subtracting 45 from 768 and dividing the result by 75. The closest answer option is D, with x = 7, but the calculation gives approximately 2.5 months.
Step-by-step explanation:
To solve how many weeks Edmond needs to save up to buy the computer, we need to write an equation involving the money he already has ($45), the amount he deposits weekly ($75/week) from his babysitting job, and the total cost of the computer ($768). Since he earns $90 per week and plans to deposit $75 into his account, it means that each week he spends the remaining $15. Therefore, the correct equation that represents this situation is the initial amount ($45) plus the amount saved each week ($75) times the number of weeks (x), which should equal the total amount required to purchase the computer ($768). Using these values, the equation is 45 + 75x = 768. To find out the number of weeks, we solve for x:
45 + 75x = 768
75x = 768 - 45
75x = 723
x = 723 / 75
x ≈ 9.64
Since we cannot have a fraction of a week in this context, we round up to the next whole week. So Edmond needs approximately 10 weeks to save enough money for the computer. To convert weeks into months, knowing that each month has 4 weeks, we calculate:
10 weeks ÷ 4 weeks/month = 2.5 months
Hence, Edmond will need about 2.5 months to save up for the computer.