1. the original price of a backpack is $40.90. the sale price is 30% off. write two different expressions to represent its sale price

2. explain how you could find the sale price of the backpack using two operations: )

$40.90 - $12.27 = $28.63 and 0.700 x $40.90 = $28.63

Step-by-step explanation:

First, convert the 30% to a real mathematical number. For percents, this is always done by dividing the 30% by 100%, or 30% / 100% = 0.300.

Second, find out what 30% of $40.90 is. This is the amount of the sale discount. This is always found by mulitplying 0.300 by the item's cost $40.90, like this:

0.300 x $40.90 = $12.27.

So for this sale, you'll save $12.27 on this item.

This means, the cost of the item to you is  

$40.90 - $12.27 = $28.63.

Or you can think about it this way. The item is 30% off. This means you'll pay 70.000% of the total cost (100% - 30% = 70.000%).

Now what's 70.000% of the total cost?  

0.700 x $40.90 = $28.63.

marco saved more.   he saved $35 more.

step-by-step explanation:

1+2+3+4+5+6+7+8+9+10 = 55

2*10 = 20

55-20 = 35