Question

In a box of electric bulb, 10% are defective. If 171 bulb are good , how many bulb are defective?

Answer 1

Answer: 18 bulbs

Step-by-step explanation:

Defective bulbs= 10%

Total bulbs= 100%

So, good bulbs= (100 - 10)% = 90%

Let the total no. of bulbs be x.

So, according to the problem

90% of x = 171

90/100 * x=171

x = 171 * 100/90

x= 171* 10/9

x= 19 * 10

x= 190

So, no. of defective bulbs= total bulbs - good bulbs = 190 - 171= 18.

Answer 2

Answer:

19 bulbs are defected

Step-by-step explanation:

Given:

• Percentage of bulbs which are defective = 10%
• No. of bulbs which are good = 171

To find :

• No. of bulbs which are defective

Let the total number of bulbs be X

according to the question,

90/100×X = 171

X=171×100/90

X=171×10/9

X=190

The total number of bulbs which are available is equal to 190

Defective bulbs = 10/100×190

Defective bulbs = 1/10×190

defective bulbs = 19

There are 19 defective bulbs totally