Beginning Algebra Tutorial 15


Beginning Algebra
Answer/Discussion to Practice Problems
Tutorial 15: Introduction to Problem Solving


WTAMU > Virtual Math Lab > Beginning Algebra > Tutorial 15: Introduction to Problem Solving


 

checkAnswer/Discussion to 1a

The sum of a number and 2 is 6 less than twice that number.
 

Step 1: Understand the problem.

Make sure that you read the question carefully several times. 

Since we are looking for a number, we will let 

x = a number
 

Step 2:  Devise a plan (translate).

ad1a1
 

Step 3:  Carry out the plan (solve).

 
ad1a2
*Get all the x terms on one side

*Inv. of add 2 is sub. 2
 

*Inv. of mult. by -1 is div. by -1

 
 

Step 4:  Look back (check and interpret).

If you take the sum of 8 and 2 it is 6 less than twice 8, so this does check.
 

FINAL ANSWER: 

The number is 8.

(return to problem 1a)
 


 

checkAnswer/Discussion to 1b

A rectangular garden has a width that is 8 feet less than twice the length.  Find the dimensions if the perimeter is 20 feet.
 

Step 1: Understand the problem.

Make sure that you read the question carefully several times. 

We are looking for the length and width of the rectangle.  Since width can be written in terms of length, we will let

L = length

Width is 8 feet less than twice the length:

2L - 8 = width
 

Step 2:  Devise a plan (translate).

ad1b1
 

Step 3:  Carry out the plan (solve).

 
ad1b2

*Mult. (  ) by 2
*Combine like terms

*Inv. of sub. 16 is add 16

*Inv. of mult. by 6 is div. by 6

 
 

Step 4:  Look back (check and interpret).

If length is 6, then width, which is 8 feet less than twice the length, would have to be 4.  The perimeter of a rectangle with width of 4 feet and length of 6 feet is 20 feet.

FINAL ANSWER: 

Width is 4 feet.

Length is 6 feet.

(return to problem 1b)
 


 

checkAnswer/Discussion to 1c

Complimentary angles, sum up to be 90 degrees.  Find the measure of each angle in the figure below.  Note that since the angles make up a right angle, they are complementary to each other.

problem 1e
 

Step 1: Understand the problem.

Make sure that you read the question carefully several times. 

We are already given in the figure that

x = 1 angle

x + 30 = other angle
 

Step 2:  Devise a plan (translate).

ad1c1
 

Step 3:  Carry out the plan (solve).

 
ad1c2

*Combine like terms

*Inv. of add 30 is sub. 30

*Inv. of mult. by 2 is div. by 2

 
 

Step 4:  Look back (check and interpret).

If x is 30, then x + 30 = 60.  60 and 30 do add up to be 90, so they are complementary angles.

FINAL ANSWER:

The two angles are 30 degrees and 60 degrees.

(return to problem 1c)
 

Buffalo Top

 

WTAMU > Virtual Math Lab >Beginning Algebra >Tutorial 15: Introduction to Problem Solving


Last revised on July 26, 2011 by Kim Seward.
All contents copyright (C) 2001 - 2011, WTAMU and Kim Seward. All rights reserved.