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.
Answer:
The one showing only the point (10, 3)
Or the linear plot with the point +10 highlighted.
Step-by-step explanation:
Answer:
x = 9
Step-by-step explanation:
The two angles are alternate exterior and has same measurement
15(x+1) = 150 divide both sides by 15
x + 1 = 10 subtract 1 from both sides
x = 9
Answer:
sin²x = (1 - cos2x)/2 ⇒ proved down
Step-by-step explanation:
∵ sin²x = (sinx)(sinx) ⇒ add and subtract (cosx)(cosx)
(sinx)(sinx) + (cosx)(cosx) - (cosx)(cosx)
∵ (cosx)(cosx) - (sinx)(sinx) = cos(x + x) = cos2x
∴ - cos2x + cos²x = -cos2x + (1 - sin²x)
∴ 1 - cos2x - sin²x = (1 - cos2x)/2 ⇒ equality of the two sides
∴ (1 - cos2x) - 1/2(1 - cos2x) = sin²x
∴ 1/2(1 - cos2x) = sin²x
∴ sin²x = (1 - cos2x)/2
