MHB Solving Ratios & Proportions Questions - Get Help Here!

[Eabzolid]

Hi. I'm doing some questions about ratio and proportions. I'm just having difficulty with some of the questions and i hope you guys can help. So question 1:

A length of chain 15'-3" long weighs 78lbs. How long would a similar chain be if it weighs 102lbs. (Answer to nearest inch)
Length =_______' _______"

If you can just kind of lead me to how to get the answer, it would be great. Thanks.

 

[MarkFL]

Let's let $L$ be the length in question...that the chain is similar implies a constant length per weight ratio, and so we may state:

$$\frac{L}{102}=\frac{183}{78}$$

I converted the length of the 78 lb. chain to inches, since we are to round $L$ to the nearest inch.

Now, solve for $L$...what do you find?

 

[Eabzolid]

183/78= 2.346

Do I need to convert that to feet?

Thanks

 

[MarkFL]

183/78= 2.346

Do I need to convert that to feet?

Thanks

The RHS of the equation I posted is not the value of $L$...you need to solve that equation for $L$. :D

 

[Eabzolid]

The RHS of the equation I posted is not the value of $L$...you need to solve that equation for $L$. :D

Oh okay.

I got 239.30. Do I then convert that to get feet and inches as my answer?

Thanks

 

[MarkFL]

Oh okay.

I got 239.30. Do I then convert that to get feet and inches as my answer?

Thanks

First, round the number you correctly found to the nearest inch, thus:

$$L\approx239$$

Now, since the length of the first chain was given in feet and inches, I would convert this to the same format. :D

 

[Eabzolid]

First, round the number you correctly found to the nearest inch, thus:

$$L\approx239$$

Now, since the length of the first chain was given in feet and inches, I would convert this to the same format. :D

Okay. I'll try

I'm just wondering if there is a formula I should follow? Or does it all depend on what the question is asking.

I got more questions that has 3 ratio number like 9:4:1.

Is it always converting when it comes to these questions?

Thanks

 

[MarkFL]

For this problem, since the chains were said to be similar, I took this to mean the length per weight ratio would be the same for both chains. So, I decided to label the unknown length $L$, and then equate the length/weight of the two chains and then solve for the unknown length. :D

 

[Eabzolid]

May I ask another question?

 

[MarkFL]

May I ask another question?

If it pertains to the problem posted in this thread, that is, if it is a follow-up question to the chain problem, then please post it in this thread. If you wish to ask about another problem, then please begin a new thread for the new problem. :D