Question

1. michael saves $423 dollars a month for college.

a. about how much money will he have saved after 4 years?
h = 4x12 = 48 months
s = 423x48 423 = 400 48 = 50
s = 400x50 = 20000
he will save 20000 after 4 years.
b. will your estimate be lower or higher than the actual amount michael will save? how do you know?

Explanation:

Step1: Calculate total months

There are 12 months in a year. For 4 years, the total number of months $n = 4\times12=48$ months.

Step2: Estimate savings amount

We estimate 423 as 400 and 48 as 50. The estimated savings $S = 400\times50 = 20000$ dollars.

Step3: Analyze the estimate

We decreased 423 to 400 (a decrease of 23) and increased 48 to 50 (an increase of 2). Since $23\times48>423\times2$, the decrease in the first - factor is more significant than the increase in the second - factor. So the estimate is lower than the actual amount.

Answer:

a. He will save about 20000 dollars after 4 years.
b. The estimate is lower than the actual amount. Because when estimating, we decreased the monthly - saving amount by 23 and increased the number of months by 2, and the decrease in the monthly - saving amount has a greater impact on the product than the increase in the number of months.