Answer: 1 hour
Step-by-step explanation:
Let the distance they walked be
in time
and the distance they walked be
in time
,then
Walking speed=

Riding speed=

Also the total time taken=3 hours
∴
...(1)
Since the total distance= 20 km
∴![d_1+d_2=20\\\Rightarrow4t_1+12t_2=20\\\Rightarrow4t_1+12(3-t_1)=20..............[\text{from (1)}]\\\Rightarrow4t_1+36-12t_1=20\\\Rightarrow-8t_1=-8\\\Rightarrow\ t_1=1](https://tex.z-dn.net/?f=d_1%2Bd_2%3D20%5C%5C%5CRightarrow4t_1%2B12t_2%3D20%5C%5C%5CRightarrow4t_1%2B12%283-t_1%29%3D20..............%5B%5Ctext%7Bfrom%20%281%29%7D%5D%5C%5C%5CRightarrow4t_1%2B36-12t_1%3D20%5C%5C%5CRightarrow-8t_1%3D-8%5C%5C%5CRightarrow%5C%20t_1%3D1)
Thus, the they spent 1 hour time in walking.
A cross section is the intersection of a solid an a plane
The question is an illustration of equivalent ratios.
- 3 cups of dark orange require 3 ounces of yellow paint
- 3 cups of light orange require 19.5 ounces of yellow paint
1 cup of dark orange requires


To make 3 cups, we simply multiply by 3, because 
So, we have:


2 cups of light orange require


To make 3 cups, we simply multiply by 1.5, because 
So, we have:


Hence:
- 3 cups of dark orange require 3 ounces of yellow paint
- 3 cups of light orange require 19.5 ounces of yellow paint
Read more about equivalent ratios at:
brainly.com/question/18441891
You should write a ( real world situation ) question that can only have whole numbers as a solution because you would divide and then you can not have a fraction left over so instead you add one. For instance there are 132 students going on a field trip. 20 students can fit on each bus. how many buses are needed? 7 because when you divide 132 by 20 you get 6 remainder 12. You can not just make 12 students walk to the location so you would add an extra bus.