I will mark as the brainliest.
A boy runs for 10 mins at a uniform speed for 9 km/h. At what speed should he run for further 20 mins, so that his average speed is 12km/h?
Answers
Answered by
0
Explanation:
ANSWER
s
1
=v
1
t
1
And, s
2
=v
2
t
2
Average speed v=
t
s
=
t
1
+t
2
s
1
+s
2
⟹v=
t
1
+t
2
v
1
t
1
+v
2
t
2
⟹v
2
=
t
2
v(t
1
+t
2
)−v
1
t
1
⟹v
2
=
20
12(10+20)−9×10
⟹v
2
=13.5km/h
Answered by
1
Answer:
hello
Explanation:
Boy runs for first 10 min at 9 kmph = 9 km/hr
Let boy run for next 10 min at V kmph
let boy run for next 10 min at V kmph
His average speed is average of above three.
Average speed = (9+ 2 V) / 3 = 12 kmph
So 9 + 2 V = 3 * 12 = 36
2 V = 36 - 9 = 27
V = 27/2 = 13.5 km/hr
please make me brainliest
Similar questions