Help needed with childs homework

TonyDebs

Hi all

My child has been sent home with the following homework,

(HCM41) Cross Over Weights (Look on Google)

"Two scouts and two cub scouts are at an adventure camp.

They need to cross the river.

Their small canoe can carry any weight up to 75kg

What is the least number of canoe trips needed to get everyone accross?

The boys weigh 60kg, 55kg,35kg and 30kg

Also their is a dog as well. It weighs 12kg, on which trip should the dog board the canoe?

Hopefully someone will be able to help us with these questions..

Thanks

Debs

Counting_Pennies_2

Am I missing something, surely it is 3 trips

60kg and possibly 12 kg dog

55kg and possibly 12 kg dog

35kg and 30kg

hth

mumofthreemonkies83

I would have said 3 trips

The dog and the 60kg
the 55kg alone
then the last 2, 30 +35kg together?

Could (and probably will) be wrong though

Mumof4 xx

CyCo_2

But how do they get the canoe back to the other side?

david39

Isn't the point of the question that someone has to bring the boat back again, so although two people go across, one of them has to bring the boat back for the others (unless the dog can row!)

msb5262

I think I'm missing something here - how does the canoe get back each time? The 60kg child can only travel with the dog, surely!

MarzipanFish

It might be 3, I've not worked it out but I think you're missing that the canoe can't get back to the original side by itself!

I couldn't find it on google but it's definitely there somewhere because I've seen it online before without it being about scouts.
I remember a step involving 2 going across, both getting out & then a different one bringing it back to the other side.


oops, I was really slow posting there!

clairec79

30kg and 35kg go across 65kg - trip 1 (side A now dog, 55kg and 60kg SIDE B 35 and 30kg)
35kg boy comes back 35kg - trip 2 (side A dog, 55kg, 60kg, 35kg SIDE B 30kg)
60kg and dog go over - 72kg trip 3 (side A 55kg, 35kg, SIDE B 60kg, dog, 30kg)
30kg boy comes back - 30kg trip 4 (side A 55kg, 35kg, 30kg, SIDE B 60kg dog)
30kg and 35kg go back - 65kg trip 5 (side A 55kg SIDE B 60kg, dog, 30kg, 35kg)
30kg comes back - trip 6 (SIDE A 55kg 30kg SIDE B 60kg, 35kg Dog)
55kg gos over alone - 55kg trip 7 (SIDE A 30kg SIDE B 60kg, 55kg, 35kg, Dog)
35kg row back - 35kg trip 8 (SIDE A 30kg, 35kg SIDE B 60kg, 55kg, Dog)
30kg and 35kg go back together - final trip - TRIP NINE (SIDE A - noone, SIDE B 60kg, 55kg, 35kg, 30kg, dog)

the only time they can have 2 boys in the boat is the two little boys, bless them they will be knackered. Otherwise you've getting into tying ropes to the boat and pulling it back empty

The dog could also go with the 55kg boy but it's the same number of trips

Mrs_Arcanum

This is similar to the one with a Goat, a Wolf, a cabbage & a farmer.

lidlest

My son figured this out it was taking me ages LOL

Ok 35 and 30 go across
30 comes back (then stays)
60 and dog goes across
35 comes back
30 and 35 go across
30 comes back
75 goes across
35 comes back and picks up 30

could possibly do it quicker than that lol

MarzipanFish

I've done 5 trips, I think it's the same as the others posted. Good way to start my saturday morning :P

65 a
55 b
35 c
30 d
12 e


step 1 c&d across
(d comes back)

step 2 a goes across
(c swaps & brings back)

step 3 c&d across again
(d comes back)

step 4 b & e(dog)
(c swaps & comes back)

step 5 c&d go across




Anyone want to do anymore river puzzles? :P
I remember the wolf (or lion)/sheep/cabbage one and there's one with cannibals too