If 3 brothers weigh 80 pounds, 120 pounds and 135 pounds, and the smallest brother gained 15 pounds over the past year, while the largest brother lost 5 pounds, the new weights of the brothers are:

95 pounds, 120 pounds, and 130 pounds.  (The middle brother's weight did not change.)

Given that the average is found by dividing the sum of the numbers in a list by the number of items in that list, the following equation will be used:

Therefore, the new average is 115 pounds. 

If 25 percent of a number is 3, then that means that 100 percent of the number will be equal to 3 times 4, which is 12. Two thirds of the number 12 is 8; therefore, 8 is the correct answer. 

Amanda has 3 more marbles than Jason and 5 fewer marbles than Kate. Together, they all have 17 marbles. 

To solve this problem, we should experiment by picking a number for Amanda. We can pick the number 4. 

If Amanda has 4 marbles, this means that Jason has 1 marble, since Amanda has 3 more. If she has 5 fewer marbles than Kate, that means that Kate must have 9 marbles. 

This leaves us with:

Amanda - 4 marbles 

Jason - 1 marble

Kate - 9 marbles

This adds up to a total of 14 marbles. However, we know that there are a total of 17 marbles. Thus, each child must have 1 more marble than what is stated above. The correct information would be below:

Amanda - 5 marbles 

Jason - 2 marble

Kate - 10 marbles

Here, the sum of the marbles is 17 and Amanda still has 3 more marbles that Jason and 5 fewer marbles that Kate. 

Thus, the correct answer is that Amanda has 5 marbles.

Divide: 

Answer: It will take Stephanie  hours to arrive.

Divide:

Answer: Each friend will receive .

When we round a number to the nearest hundredth we look to the thousandths place to tell us if we round up or down.

If the number in our thousandths place is  or greater, we round up. If the number in the thousandths place is  or less, we round down. When we round up, the number in the thousandths place increases by  and all the other numbers to the right become . When we round down, the number in the thousandths place stays the same and all the other numbers to the right become .

In this case,  is greater than  so our rounded number is  or 

When we round a number to the nearest hundredth we look to the thousandths place to tell us if we round up or down.

If the number in our thousandths place is  or greater, we round up. If the number in the thousandths place is  or less, we round down. When we round up, the number in the thousandths place increases by  and all the other numbers to the right become . When we round down, the number in the thousandths place stays the same and all the other numbers to the right become .

In this case,  is less than  so our rounded number is  or 

When we round a number to the nearest hundredth we look to the thousandths place to tell us if we round up or down.

If the number in our thousandths place is  or greater, we round up. If the number in the thousandths place is  or less, we round down. When we round up, the number in the thousandths place increases by  and all the other numbers to the right become . When we round down, the number in the thousandths place stays the same and all the other numbers to the right become .

In this case,  is less than  so our rounded number is  or 

When we round a number to the nearest hundredth we look to the thousandths place to tell us if we round up or down.

If the number in our thousandths place is  or greater, we round up. If the number in the thousandths place is  or less, we round down. When we round up, the number in the thousandths place increases by  and all the other numbers to the right become . When we round down, the number in the thousandths place stays the same and all the other numbers to the right become .

In this case,  is greater than  so our rounded number is  or 

When we round a number to the nearest hundredth we look to the thousandths place to tell us if we round up or down.

If the number in our thousandths place is  or greater, we round up. If the number in the thousandths place is  or less, we round down. When we round up, the number in the thousandths place increases by  and all the other numbers to the right become . When we round down, the number in the thousandths place stays the same and all the other numbers to the right become .

In this case,  is less than  so our rounded number is  or