Simple Maths Question (part 2)

[dr_gn]

CaptainSlow said:

dr_gn said:

CaptainSlow said:

dr_gn said:

Where exactly does it say that?

The second sentence says exactly that. Anyhow, what is the answer?

It says there is an overlap of 0.5m, not that you lose 0.5m per piece in the join. Two different results.

What is the answer? Depends on the question I guess?

It says you lose 0.5 overlap per rope...ie per piece. Assume the answer doesn't support your interpretation.

It actually doesn’t say that at all.

It doesn’t say you “lose” anything, anywhere in the question. You’re adding a word to support your interpretation, whereas I’m just answering the question.

It simply says they overlap by 0.5m per piece. For all we know, “tied” could mean joined in parallel with bits of string, or a knot in the middle of the 0.5 overlaps.

[anonymous-user]

The question is not ambiguous in any way. Nor is the answer. The answer is 48m. It does not matter how the ropes are joined, glued, knotted etc.

The distance between the start of the structure and the mid-point of the first joint is 9.75m; similarly the distance between the mid-point of the last join and the end of the chain.

The distance between the intermediate midpoints of the joins is 9.5m

The length of the structure is (2*9.75)+(3*9.5) = 48

Period.

ETA: cross-posted with above (correct) depiction.

[dr_gn]

Hang On said:

The question is not ambiguous in any way. Nor is the answer. The answer is 48m. It does not matter how the ropes are joined, glued, knotted etc.

The distance between the start of the structure and the mid-point of the first joint is 9.75m; similarly the distance between the mid-point of the last join and the end of the chain.

The distance between the intermediate midpoints of the joins is 9.5m

The length of the structure is (2*9.75)+(3*9.5) = 48

Period.

ETA: cross-posted with above (correct) depiction.

Thank you.

Now let’s say we’ve got 2 cakes...

[CaptainSlow]

Your picture shows only one rope overlapping.

So what was the answer in the booklet?

[V8LM]

Not ambiguous to me. Actually a good question because first answer to many might be 46 or 47.5 (four knots with 1 m per knot or 5 pieces of rope at 0.5 m per piece).

Answer is 48


Edit as I couldn’t do 50 - 2.5

Edited by V8LM on Monday 5th February 07:29

[dr_gn]

CaptainSlow said:

Your picture shows only one rope overlapping.

What on Earth are you on about?

[dr_gn]

Answer in the book is:



Again, like the cake fraction question, it’s the wrong answer to the question asked.

In both cases I can see what they were wanting to achieve, but in trying to put the question into real-world context, they screwed up the English.

[V8mate]

The question is certainly ambiguous. If you tied a knot at the 0.5m mark on each rope, you'd have dangly bits that didn't contribute to the overall length.



But the question can, equally, be read as per the diagrams in previous responses^^.

Edited by V8mate on Monday 5th February 08:16

[Fast and Spurious]

Hang On said:

The question is not ambiguous in any way. Nor is the answer. The answer is 48m. It does not matter how the ropes are joined, glued, knotted etc.

The distance between the start of the structure and the mid-point of the first joint is 9.75m; similarly the distance between the mid-point of the last join and the end of the chain.

The distance between the intermediate midpoints of the joins is 9.5m

The length of the structure is (2*9.75)+(3*9.5) = 48

Period.

ETA: cross-posted with above (correct) depiction.

It's 46m. It clearly says the ropes are tied, don't overcomplicate things. The drawing above is wrong. Also, what's a "Period"?

[Fast and Spurious]

dr_gn said:

Answer in the book is:



Again, like the cake fraction question, it’s the wrong answer to the question asked.

In both cases I can see what they were wanting to achieve, but in trying to put the question into real-world context, they screwed up the English.

Don't overthink it. Maybe Maths isn't your subject, speak with your tutor if you need some extra help.

[CaptainSlow]

dr_gn said:

CaptainSlow said:

Your picture shows only one rope overlapping.

What on Earth are you on about?

If the question had stated "the ropes overlap by 0.5m" you'd be correct, however, as it states "there is an overlap of 0.5m per bit of rope" you're incorrect.

The answer is 46m.

[dr_gn]

Fast and Spurious said:

Hang On said:

The question is not ambiguous in any way. Nor is the answer. The answer is 48m. It does not matter how the ropes are joined, glued, knotted etc.

The distance between the start of the structure and the mid-point of the first joint is 9.75m; similarly the distance between the mid-point of the last join and the end of the chain.

The distance between the intermediate midpoints of the joins is 9.5m

The length of the structure is (2*9.75)+(3*9.5) = 48

Period.

ETA: cross-posted with above (correct) depiction.

It clearly says the ropes are tied

Yes, and if they’re tied like this, as per the question (an overlapping join), then the answer is clearly NOT 46m



For the hard of thinking: substitute rope for the steel bar.

[DanL]

dr_gn said:

Yes, and if they’re tied like this, as per the question (an overlapping join), then the answer is clearly NOT 46m



For the hard of thinking: substitute rope for the steel bar.

That was the mental image I had from the question. Seems I don’t think mathematically.

[Toltec]

dr_gn said:

Yes, and if they’re tied like this, as per the question (an overlapping join), then the answer is clearly NOT 46m



For the hard of thinking: substitute rope for the steel bar.

That raises an interesting point, in the drawing the overlap is specified based on the rod diameters. If the ropes in the question are say 10mm then a total joint loss of half a metre, i.e a 25cm tail on each side to form a knot sounds sensible, but a 50cm tail is too much. If the ropes are 50mm then a 25cm tail is not really going to work so a 50cm one sounds more sensible. Well, as sensible as buying rope in 10m lengths is.

The stated answer shows what the setter was trying to imply by the per rope phrasing though.

[DamienB]

Christ, am I the only person thinking the answer is just 5 x 10 = 50m? I don't give a st how you tie them together, their total length should not be subject to the angle at which any particular portion of the rope is lying at. I paid for 5 x 10 and I've got 5 x 10.

[boyse7en]

DamienB said:

Christ, am I the only person thinking the answer is just 5 x 10 = 50m? I don't give a st how you tie them together, their total length should not be subject to the angle at which any particular portion of the rope is lying at. I paid for 5 x 10 and I've got 5 x 10.

How are you going to tie five lengths of 10m rope together to get 50m??? They would have to be laid end to end, which means you have nothing to tie together.

[dr_gn]

boyse7en said:

DamienB said:

Christ, am I the only person thinking the answer is just 5 x 10 = 50m? I don't give a st how you tie them together, their total length should not be subject to the angle at which any particular portion of the rope is lying at. I paid for 5 x 10 and I've got 5 x 10.

How are you going to tie five lengths of 10m rope together to get 50m??? They would have to be laid end to end, which means you have nothing to tie together.

Tie them in triple granny knots if you like, total length of rope is still 50m cos you’ve not cut it and thrown anything away. It’s just not a continuous length of 50m.