Math Is Easy - Use Algebra To Solve Word Problem 1!

 

If 27 is subtracted from three times a certain number, the result is 18. Find the number. (Note 1)

 

If we let n represent the number to be found, the sentence “If 27 is subtracted from three times a certain number, the result is 18.”can be translated into the following algebraic equation:

3n – 27 = 18

 

Solve this equation

3n – 27 =    18

     + 27 = + 27 Add 27 to both sides

3n + 0   =    45

3n         =    45

 

3n/3      =    45/3 Divide each side by 3

 n          =    15

 

Now we substitute the solution for n into the original equation to see if it works.

3n       – 27 = 18

3(15)  – 27 = 18

45       – 27 = 18

18               = 18

 

We must also see if the solution works in the original  problem statement.

If 27 is subtracted from three times a certain number, the result is 18.

If 27 is subtracted from three times a certain number(3 X 15), the result is 18.

If 27 is subtracted from 45, the result is 18.

45 – 27 = 18

 

We have just solved a first degree equation.

 

(Note 1)

The source for the problem statement is:

“Intermediate Algebra  For College Students” by Jerome E. Kaufman

 


Close Window