Question

Shau-uen solve the equation 18.5w+6.5w-2.8w=149.1 Her work is shown below

Step(1)
18.5w+6.5w-2.8w= 149.10
Step(2)
25w-2.8w= 149.1
Step(3)
-2.8w=5.964
Step(4)
W= -2.13
In which step did Shaun make her first error?

A. Step 1
B. Step 2
C. Step 3
D. Step 4

Answer 1

the answer is

C.- step 3

Answer 2

Shaun make her first error in step 3. Answer C

Explanation:

If have the same units you can simply add them, Like this:

Step (1)

18.5w+6.5w-2.8w= 149.10 (everything in the left side is in terms of w)

Step(2)

25w-2.8w= 149.1 (add 18.5+6.5)

Step(3)

Here you have to add the terms of w

(25-2.8)w=149.1

22.2w=149.1

Step(4)

Here you clear w

w=149.1/22.2

w=6.72