Question

A gear in a machine makes 49 revolutions per hour. About how many revolutions does the gear make in 5 days?

Create an expression to model the given situation. Then, use estimation strategies to find approximately how many revolutions the
gear makes in 5 days.
1,200
5,000
24
60
50
10
40
6,000
x 12 x 49
$ 120

Answer 1

Estimated: 6000 revolutions

Actual: 5880 revolutions

Step-by-step explanation: (Estimation)

First, we should round 49 to 50.

Next, we should convert 5 days to hours to match the per hour rule.

5 days --> 120 hours

Then, multiply 120 by 50 to get 6000 or you can take out the 0 in 120 so it might be easier for you.

(Acutal)

First, Convert 5 days to 120 hours to match the per hour rule.

Next, multiply 120 by 49 to get 5880 or take out the 0 in 120 to make it easier for you.

Answer 2

24, 10, 50, 6,000 (They are in order)

Explanation:

It is given that the gear makes 49 revolutions per hour. So, to determine an expression to represent the number of revolutions a gear makes in 5 days, multiply the product of 5 days and 49 revolutions by 24 hours per day.

Next, use the associative property to create an equivalent expression. So, 24 is equivalent to the product of 2 and 12, and the product of 5 and 2 is 10.

In the third step, multiply 10 and 12, and estimate 49 as 50.

Finally, multiply 120 by 50.

The following shows a correct method to find the approximate number of revolutions the gear makes in 5 days.

So, the gear makes approximately 6,000 revolutions in 5 days.