On a regular day, a certain manufacturing line produces 100 units, of

Question

On a regular day, a certain manufacturing line produces 100 units, of which 1% are defective. On a rush day, the same line produces 125 units, of which 4% are defective. How many more non-defective units does the manufacturing line produce on a rush day than on a regular day?

A. 20
B. 21
C. 25
D. 120
E. 125

A. 20
B. 21
C. 25
D. 120
E. 125

rohit8865 · Answer

Defective item on regular day = 1% of 100 = 1
Non defective item =100-1=99

Defective item on rush day = 4% of 125 =5
Non defective item =125-5= 120

So, number of more non-defective units does the manufacturing line produce on a rush day than on a regular day = 120-99=21

Ans B

JeffTargetTestPrep · Answer

We are given that on a regular day, a certain manufacturing line produces 100 units, of which 1% are defective. Thus, on a regular day, 0.01 x 100 = 1 unit is defective and 99 are not defective.

On a rush day, the same line produces 125 units, of which 4% are defective. Thus, on a rush day, 0.04 x 125 = 5 units are defective and 120 are not defective.

Thus, the manufacturing line produces 120 - 99 = 21 more non-defective units

Answer: B

BillyZ · Answer

Official solution from Veritas Prep.

The math is relatively straightforward here, but this problem uses the answers to distract you from the specific verbiage of the question.

The question asks you for the difference in "non-defective" units, that is:

-  
   -   
   -   = 21

Answer choices (E) and (D) represent the total number of units on a rush-day, respectively. They are clearly not the answer. Happy because you avoided the obvious trap, you may also realize that Answer choice (C), 25 is the difference between the non-adjusted amount on a rush-day and the non-adjusted amount on a regular day.

Adjust the rush day to account for defects, and you are left with 120 non-defective units. Here you may be tempted to select Answer choice (A). However, remember the you must also adjust the regular day. There are only 99 non-defective units on the regular day. Therefore the correct answer is (B).

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