An explorer wants to cross a desert that is 7 km long. He can walk 1 km per day and he must drink one bottle of water a day. A maximum of 5 bottles of water can be taken from the village. At least how many days does the explorer need to cross the desert ? A) 10. B) 12. C) 13. D) 8
Answers
Answer:
(c) 13 days
Step-by-step explanation:
The journey is spilt into 2 parts:
Part 1:
1. Take 3 bottles
2. Walk for 1 km
3. Leave a bottle behind
4.. Walk back 1 km to the village
5. Take 5 more bottles
6. Walk for 2 km
7. Leave a bottle behind
8. Walk 2 km back to the village
Total distance covered so far = 1 + 1 + 2 + 2 = 6 km
Number of days taken = 6 days
Part 2:
1. Take 5 bottles
2. Walk 1 km
3. Drink 1 bottle and pick up the one left behind in part 1 (Qty left = 5)
4. Walk 1 km
5. Finish up 1 bottle and take the bottle left behind earlier (Qty left = 5)
6. Walk 5 km
Total distance covered so far = 1 + 1 + 5 = 7 km
Number of days taken = 7 days
Find the total number of days needed for the whole journey:
Total days = 6 + 7 = 13 days
Answer: (C) 13 days
Answer:
B)12
Step-by-step explanation:
The length of the desert= 7 km
He can walk 1 km per day
He must drink 1 bottle per km
Maximum 5 bottles can be take from the village
days needed to cross the desert = ?
Now
On the first day
He walks with 5 bottles
in one day he travel 1 km and reach point A and spends 1 bottle
bottles left =4
he leave 3 bottles their
total bottles left =1
on the second day he return back to village bottle spent =1 and bottles left =0 with him
Now he take 5 more bottles from village
on third day he travel 1 km and leave point A in one day where he left his 3 bottles
Now he has 7 bottles in total
Now on fourth day from point A he take 5 bottles, he reach point B with 4 bottles and leave 3 bottles there at point B
With one bottle left in hand at B
he come back to take the bottles left at point A on fifth day now he has 2 bottles
and he moves to point B on sixth day with 5 bottles in hand
remaining km equal to = 6
and he has 6 bottles
so he will cover it in 6 days
total days = 6+6= 12
So he will take 12 days in total to cross the desert