If 1/3 workers take public transportation and 2/5 drive cars what fraction of the workers walk to work ?

Question

I need to understand how the answer is 4/15

Answer 1

The solution to this problem assumes that there only three options for workers to get to work - public transport, driving, walking. The sum of fractions of the three options must add to 1.

 

Let us assume that the fraction of workers that walk to work is x.

 

1/3 + 2/5 + x = 1

 

The LCM of 3 and 5 is 15, so we need to make 15 the denominator of all the fractions

 

5/15 + 6/15 + x = 15/15

 

11/15 + x = 15/15

 

We can now subtract 11/15 from both sides of the equation to get the value of x

 

x = 15/15 - 11/15

 

x = 4/15

 

The fraction of workers who walk to work is 4/15.

Answer 2

Write an equation that shows the total fraction of the workers who took their own mode of transportation.

 

Let x = the number of workers who walked

 

 

Your equation is then

 

(1 / 3) + (2 / 5) + x = 1

 

 

Isolate x by moving all the constant terms to the right side.

 

x = 1 - (1 / 3) - (2 / 5)

 

 

Next, find the LCD of the terms on the right side of the equation.  The LCD is 15.

 

x = (15 / 15) - (5 / 15) - (6 / 15)

 

 

Now, we can add the numerators on the right side of equation giving us the final answer.

 

x = 4 / 15

Answer 3

All the above are fractions of the whole. If we add 1/3 + 2/5 we get 11/15. The equivalent fractions are 5/15 and 6/15. 

 

1 - 11/15 = 4/15