Answer:
Option (3)
Step-by-step explanation:
Option (1).
AB and SE are coplanar.
Incorrect.
AB lies in a plane ABS and SE lies in another plane SEL.
Option (2).
TS and SE intersect at E.
Incorrect.
They intersect at S.
Option (3).
R intersects K at SB.
Correct.
Since line of intersection of planes R and K is SB
Option (4)
AB and BL are perpendicular at B.
Incorrect.
Angle between them is not 90°.
It took him 2.6 hours to reach the top
Data;
- Uphill = 6km
- Downhill = 4km
- Total time taken = 8 hours
<h3>Speed</h3>
Let us calculate the speed during uphill and downhill
Since the time it took them to descend is twice the time it took them to ascend,
- Let x represent the time taken to ascend

From the calculation above, it took him 2.6 hours to reach the top.
Learn more on speed here;
brainly.com/question/4931057
Answer:
x = 50
m∠D = 150°
m∠F = 30°
Step-by-step explanation:
- supplementary angles are two angles whose sum is 180°
∠D + ∠F = 180°
3x + x - 20 = 180
3x + x = 180 + 20
4x = 200
x = 200/4
x = 50
D = 3*50 = 150
∠D = 150°
F = 50 - 20 = 30
∠F = 30°
Answer:
x > -4
Step-by-step explanation:
— 3х + 7 < 19
Subtract 7 from each side
— 3х + 7-7 < 19-7
-3x < 12
Divide each side by -3, remembering to flip the inequality
-3x/-3 > 12/-3
x > -4