@RRITESH KAKKAR

While it occurs to me that this problem may be readily solved via the 'utilitarian route' - I encourage you to consider the 'duel equation method' --- That said, I'll count a correct answer (with work) as a correct answer

 

When the boys are 15 miles apart

what does this mean?
i mean both distance of boy? or from home of one or both?

 

When the distance intervening the boys is 15 miles -- how far has each boy walked:

So when the distance between 'boy 1' and 'boy 2' = 15 Miles

'Boy 1' has walked ___ Miles
and
'Boy 2' has walked ___ Miles

Got it?

 

Two brothers leave home at the same time and walk in opposite directions, one at 3.5 mph and the other at 4 mph. When the boys are 15 miles apart how far will each boy have walked?

So, D=Da+Db
15=3.5x + 4x
15=7.5x
x=2
Da=3.5x2=7miles
Db=4x2=8

 

Very good!

 

Here's your next exercise

Current postal regulations do not permit mailing of a package if the combined length, width and height exceed 72 inches. What are the dimensions of the largest permissible package with length twice the side of its square end?

 

dont understand the question

 

dont understand the question

Imagine a box (rectangular solid). It has a length, a width, and a height.

For instance, a box might be 12" x 5" x 10". The sum of the length, width, and height would be what? If this sum is greater than 72" the Post Office won't accept the package for shipment.

You are asked to find the dimensions of the largest box that can be shipped, but not just any box -- you are only interested in boxes that have a square end and whose remaining dimension is twice the length of (one of) the sides of the square end.

Try drawing a picture.

 

dont understand the question

Try to describe the problem via two equations
Hint: the geometry of squares is important

 

This type Sir.
the length =2x
B=x
h=x

 

dont understand the question

Length+Width+Height = 72 inches

What are the dimensions of the carton if its length is twice its width or height?

 

What are the dimensions of the carton if its length is twice its width or height?

let width be x , so height be x
and length will be 2x
4x

 

What are the dimensions of the carton if its length is twice its width or height?

let width be x , so height be x
and length will be 2x
4x

So far so good --- Now write two equations descriptive of the stipulations...

 

Sorry i dont know

 

Sorry i dont know

You're very close!

 

Solve it as you feel comfortable - I don't insist you use two equations...

 

let width be x , so height be x
and length will be 2x
4x
So far so good --- Now write two equations descriptive of the stipulations...

but what sort of equations?

 

A=length x breath
V=length x breath x height

 

A=length x breath
V=length x breath x height

Area and volume are not important in the solution of this exercise.

You were on the right track in post #332!

 

let width be x , so height be x
and length will be 2x
4x
So far so good --- Now write two equations descriptive of the stipulations...

but what sort of equations?

Equations that restate the stipulations algebraically...