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K walked at 3 kmph for a certain distance with l and thereafter at 6 kmph with M to cover a total distance of 27 km in 7 hours. Find the distance travelled with M?
- A15 km
- B12 km
- C10 km
- D9 km
Answer not set
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CCommunity
Let the time taken by K with l = x hrs and time taken by K with M = y hrs
We know that, speed × time = distance
Given that total distance = 27 km
⇒ 3x + 6y = 27 ----- equation (1)
Also given that total time taken = 7 hrs
⇒ x + y = 7 ---- equation (2)
Subtract equation (1) from 6 × equation (2), we get
⇒ 3x = 15
⇒ x = 15/3 = 5 hrs
Substitute x = 5 in x + y = 7
⇒ y = 2 hrs
∴ K travelled with M = 6y = 6 (2) = 12 km
We know that, speed × time = distance
Given that total distance = 27 km
⇒ 3x + 6y = 27 ----- equation (1)
Also given that total time taken = 7 hrs
⇒ x + y = 7 ---- equation (2)
Subtract equation (1) from 6 × equation (2), we get
⇒ 3x = 15
⇒ x = 15/3 = 5 hrs
Substitute x = 5 in x + y = 7
⇒ y = 2 hrs
∴ K travelled with M = 6y = 6 (2) = 12 km