1/2 because it's 2 times smaller
It's because a tenth means that you've divided it by 10. So if it's 20, it means you're multiplying tenths by 20, leaving you with 2 wholes.
For example, you have 2 cakes and you cut each into 10 slices, the slices are each one tenth of the whole cake, and in total there are 20 tenths.
So first you have to do 18 multiply by 2/9. This gets you 4, next you multiply by 1/2. This gets you 2.
ANSWER: She will have 2 stamps left.
Answer:
The dimensions of the can that will minimize the cost are a Radius of 3.17cm and a Height of 12.67cm.
Step-by-step explanation:
Volume of the Cylinder=400 cm³
Volume of a Cylinder=πr²h
Therefore: πr²h=400

Total Surface Area of a Cylinder=2πr²+2πrh
Cost of the materials for the Top and Bottom=0.06 cents per square centimeter
Cost of the materials for the sides=0.03 cents per square centimeter
Cost of the Cylinder=0.06(2πr²)+0.03(2πrh)
C=0.12πr²+0.06πrh
Recall: 
Therefore:



The minimum cost occurs when the derivative of the Cost =0.






r=3.17 cm
Recall that:


h=12.67cm
The dimensions of the can that will minimize the cost are a Radius of 3.17cm and a Height of 12.67cm.
Proportional:
4/7 and 10/17.5
2/3 and 9/12
18/8 and 9/4
NOT proportional:
3/8 and 6/141
7/5 and 27/50