Assume that you have to prepare a 200 g salt solution, and the concentration must be 15 % by mass. How many grams of solute and water you must mix together.

170 g

Explanation:

w/w% concentration = mass of solute/ mass of solution * 100

mass of solute = x

mass of solution = 200 g

w/w% concentration =  15 % by mass

15 = x/200 * 100

15 = 100x/200

200 * 15 = 100x

x = 200 * 15/100

x = 2 * 15

x = 30g

But mass of solution = mass of solute + mass of solvent

mass of solute = 30g

mass of solvent = mass of solution  - mass of solute

mass of solvent = 200 g - 30 g

mass of solvent = 170 g

kuchisake

kuchisake-onna (口裂け女, "slit mouth woman ") is a malevolent figure appearing in japanese ghost stories, possibly dating back to the edo period. she takes the form of a masked woman who approaches people and asks them if they believe she is pretty.

explanation:

what is the average time it took the car to travel 0.25 meters?

⇒ 2.23 seconds

what is the average time it took the car to travel 0.50 meters?

⇒ 3.13 seconds