Peggy D.

asked • 01/21/13

word problem:

Word problem:. Find the height of each building if Jefferson Square Tower is twice as tall as Lincoln Galleria and Washington Center is 120 feet taller than Lincoln Galleria. Total height 1800. Height each building?

Kyle S.

My answer won't post so I'll try to put it in the comments section instead.

1) If the total height is 1800, that means that all the heights add up to 1800. Since we don't know any of the heights, we need to give them variable names. We'll call Jefferson Square Tower x, Lincoln Galleria y, and Washington Center z. If we use these variable names with the statement that the total is 1800 we obtain the formula:

x + y + z = 1800

2) Since this formula has three variables, it is unsolvable. We need to get it down to one variable. To do this we will need the other information given in the problem. The problem says: "...Jefferson Square Tower is twice as tall as Lincoln Galleria..." We can translate this to a formula by using our variable names and putting = where "is" was and 2* where "twice" is. Using this method, we obtain:
x = 2*y

Now we need to use the same method for "...Washington Center is 120 feet taller than Lincoln Galleria." (120 feet taller means 120 +) We get the formula:
z = 120 + y

3) Now we need to use substitution and simplify the original equation so we can solve it. Our two equations tell us that we can put 2*y wherever x is and 120 + y wherever z is. If we do this to our original formula (x + z + y = 1800), we get:

2*y + y + 120 + y = 1800
Now we can solve this because we only have one variable (y). Now let's add up all the like terms.
4*y + 120 = 1800
Now we solve for y by getting y on its own side with no numbers. We need to make sure we do the same thing to both sides.

4*y + 120 -120 = 1800 - 120 (subtract 120 from both sides)
(4*y)/4 = 1680/4 (divide both sides by 4)
y = 420
So the height of the Lincoln Galleria is 420ft.
4) Now use our formulas (x = 2*y and z = 120 + y) for each other building to find their heights. But now we know what y equals (420) so we can put that in instead of y.
x = 2*420 = 840
So the Jefferson Square Tower is 840ft tall.
z = 120 + 420 = 540
So the Washington Center is 540ft tall.

Report

01/21/13

Kyle S.

My answer won;t post so I will try to put it in the comments section instead.

1) If the total height is 1800, that means that all the heights add up to 1800. Since we don't know any of the heights, we need to give them variable names. We'll call Jefferson Square Tower x, Lincoln Galleria y, and Washington Center z. If we use these variable names with the statement that the total is 1800 we obtain the formula:

x + y + z = 1800

2) Since this formula has three variables, it is unsolvable. We need to get it down to one variable. To do this we will need the other information given in the problem. The problem says: "...Jefferson Square Tower is twice as tall as Lincoln Galleria..." We can translate this to a formula by using our variable names and putting = where "is" was and 2* where "twice" is. Using this method, we obtain:
x = 2*y

Now we need to use the same method for "...Washington Center is 120 feet taller than Lincoln Galleria." (120 feet taller means 120 +) We get the formula:
z = 120 + y

3) Now we need to use substitution and simplify the original equation so we can solve it. Our two equations tell us that we can put 2*y wherever x is and 120 + y wherever z is. If we do this to our original formula (x + z + y = 1800), we get:

2*y + y + 120 + y = 1800
Now we can solve this because we only have one variable (y). Now let's add up all the like terms.
4*y + 120 = 1800
Now we solve for y by getting y on its own side with no numbers. We need to make sure we do the same thing to both sides.

4*y + 120 -120 = 1800 - 120 (subtract 120 from both sides)
(4*y)/4 = 1680/4 (divide both sides by 4)
y = 420
So the height of the Lincoln Galleria is 420ft.
4) Now use our formulas (x = 2*y and z = 120 + y) for each other building to find their heights. But now we know what y equals (420) so we can put that in instead of y.
x = 2*420 = 840
So the Jefferson Square Tower is 840ft tall.
z = 120 + 420 = 540
So the Washington Center is 540ft tall.

Report

01/21/13

Peggy D.

No answers....yet!! That's your answer in three different emails???

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01/21/13

3 Answers By Expert Tutors

By:

Kevin S. answered • 01/21/13

Tutor
5 (4)

Kyle S. answered • 01/21/13

Tutor
4.8 (129)

Software Engineer tutoring Calculus, Algebra, C++, etc.

John R. answered • 01/21/13

Tutor
4.6 (55)

John R: Math, Science, and History Teacher

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