Let's see here. Sarah is one person. Her three friends are three more. That means 4 people are decorating picture frames. However, we only have 3 rolls of ribbon! We can give an entire roll to each person, but one person would have no roll to decorate with! What do we do? We have to divide this. By definition, divide means to separate something(in this case, ribbon rolls) into (equal) parts. So, we must divide them so everyone gets an EQUAL ribbon roll length.
Answer:
0.06 liters
Step-by-step explanation:
acid concentration of 65% means that it of 100 units of that solution 65 are acid, and the remaining 35 are water.
so, 100 units are 0.2 liters in this example.
that means that 65/100 × 0.2 = 0.13 liters are acid.
35/100 × 0.2 = 0.07 liters are water
we get a 50% concentration, when we have the same amount of water and acid in the solution (acid is only half of 50% of the solution).
the account of acid remains the same, as we are only adding water.
so, how much water do we need to get from 0.07 liters to 0.13 liters (the same as the already present acid) ?
0.13 - 0.07 = 0.06 liters
Answer:
To make the cup 64.57 square inches of plastic were used.
Step-by-step explanation:
A cup has the format of a cylinder with a open top. The surface area of the cup is given by the area of it's base (a circle) and the area of it's walls, wich can be seen as rectangle where the width is the length of the circle at the base and the height is the height of the cylinder. So we have:
area of the base = pi*r^2 = 3.14*(1.75)^2 = 3.14*3.0625 = 9.616 square inches
area of the walls = 2*pi*r*h = 2*3.14*(1.75)*5 = 54.95 square inches
surface area of the cup = area of the base + area of the walls = 9.616 + 54.95
surface area of the cup = 64.57 square inches
To make the cup 64.57 square inches of plastic were used.
