How to find the missing number of a percentage

PercentageMath-home Previous Next Find the missing number in a percent expressionExample (1) 20% of ? = 25Solution:Shortcut method to find the mission number in the given expressio

How to find the missing number of a percentage

Percentage

Math-home

  • Previous
  • Next

Find the missing number in a percent expression

Example (1) 20% of ? = 25

Solution:

math percentage206

Shortcut method to find the mission number in the given expression for percent

math percentage207

Alternate method: Unitary method to find the missing number in a expression for percentage

math percentage208
math percentage209

This is called unitary method. In this method, first of value for 1(one) is calculated. Then value is multiplied by required number to get answer. Unitary method is one of the most used methods.

Example (2) 30% of ? = 600

Solution:

math percentage210
math percentage211

Shortcut method to find the mission number in the given expression for percent

math percentage212

Alternate method: Unitary method to find the missing number in a expression for percentage

math percentage213
math percentage214

Questions based on finding the missing number in a expression for percentage

Question: (1) 20% of ? = 100

Or, 20% of what number is equal to 100?

Solution:

We have to find 20% of ? = 100

math percentage215

Shortcut method:

We have to find 20% of ? = 100

math percentage216

Alternate Method: Unitary Method

We have to find 20% of ? = 100

Let, ? = 100

20% of 100 = 20

Now,

20 is the 20% of 100

1 will be the 20% of `100/20=5`

20 will be 20% of 5 × 20 = 100

Thus, required number = 100 Answer

Question: (2) 2% of ? = 45

Solution:

We have to find 2% of ? = 45

math percentage217

Shortcut Method

We have to find 2% of ? = 45

We know that, if x% of y = m

Therefore, `y=(mxx100)/x`

Here in the given question, x=2, and m = 45 thus y=?

Therefore, `y=(45xx100)/2`

y = 45 × 50

Therefore, y = 2250 Answer

Alternate Method: Unitary Method

We have to find 2% of ? = 45

Let, ? = 100

2% of 100 = 2

Now,

2 is the 2% of 100

1 will be the 2% of `100/2=50`

45 will be 2% of 50 × 45 = 2250

Thus, required number = 2250 Answer

Question: (3) 5% of ? = 200

Or, 5% of what is equal to 200?

Solution:

We have to find 5% of ? = 200

math percentage218

Shortcut Method to find the missing number in given expression of percent

We have to find 5% of ? = 200

We know that, if x% of y = m

Therefore, `y=(mxx100)/x`

Here in the given question, x=5, and m = 200 thus y=?

Therefore, `y=(200xx100)/5`

y = 200 × 20

Therefore, y = 4000 Answer

Alternate Method: Unitary Method

We have to find 5% of ? = 200

Let, ? = 100

5% of 100 = 5

Now,

5 is the 5% of 100

1 will be the 5% of `100/5=20`

200 will be 5% of 20 × 200 = 4000

Thus, required number = 4000 Answer

Question: (4) 13% of ? = 39

Or, 13% of what number is equal to 39 ?

Solution:

We have to find 13% of ? = 39

math percentage219

Shortcut Method to find the missing number in given expression of percent

We have to find 13% of ? = 39

We know that, if x% of y = m

Therefore, `y=(mxx100)/x`

Here in the given question, x=13, and m = 39 thus y=?

Therefore, `y=(39xx100)/13`

y = 3 × 100

Therefore, y = 300 Answer

Alternate Method: Unitary Method

We have to find 13% of ? = 39

Let, ? = 100

13% of 100 = 13

Now,

13 is the 13% of 100

1 will be the 13% of `100/13`

39 will be 13% of `100/13xx39`

= 100 × 3 = 300

Thus, required number = 300 Answer

Question: (5) 22% of ? = 110

Or, 22% of what number is equal to 110 ?

Solution:

We have to find 22% of ? = 110

Let 22% of `y` = 110

`=>22/100xx\y=110`

After cross multiplication

22`y` = 110 × 100

`=> y = (110xx100)/22`

= 5 × 100 = 500

Thus, required number = 500 Answer

Shortcut Method to find the missing number in given expression of percent

We have to find 22% of ? = 110

We know that, if x% of y = m

Therefore, `y=(mxx100)/x`

Here in the given question, x=22, and m = 110 thus y=?

Therefore, `y=(110xx100)/22`

y = 5 × 100 = 500

Therefore, y = 500 Answer

Alternate Method: Unitary Method

We have to find 22% of ? = 110

Let, ? = 100

22% of 100 = 22

Now,

22 is the 22% of 100

1 will be the 22% of `100/22`

110 will be 22% of `100/22xx110`

= 100 × 5 = 500

Thus, required number = 500 Answer

Question: (6) 13% of ? = 65

Or, 13% of which number will be equal to 65 ?

Solution:

math percentage221

Shortcut Method to find the missing number in given expression of percent

We have to find 13% of ? = 65

We know that, if x% of y = m

Therefore, `y=(mxx100)/x`

Here in the given question, x=13, and m = 65 thus y=?

Therefore, `y=(65xx100)/13`

`y` = 5 × 100 = 500

Therefore, required number = 500 Answer

Alternate Method: Unitary Method

We have to find 13% of ? = 65

Let, ? = 100

13% of 100 = 13

Now,

13 is the 13% of 100

1 will be the 13% of `100/13`

65 will be 13% of `100/13xx65`

= 100 × 5 = 500

Thus, required number = 500 Answer

Question: (7) 22% of ? = 88

Or, 22% of what number is equal to 88?

Solution:

We have to find 22% of ? = 88

math percentage222

Shortcut Method to find the missing number in given expression of percent

We have to find 22% of ? = 88

We know that, if x% of y = m

Therefore, `y=(mxx100)/x`

Here in the given question, x=22, and m = 88 thus y=?

Therefore, `y=(88xx100)/22`

`y` = 4 × 100 = 400

Therefore, required number = 400 Answer

Alternate Method: Unitary Method

We have to find 22% of ? = 88

Let, ? = 100

22% of 100 = 22

Now,

22 is the 22% of 100

1 will be the 22% of `100/22`

88 will be 22% of `100/22xx88`

= 100 × 4 = 400

Thus, required number = 400 Answer

Question: (8) 12% of what number is equal to 60?

Solution:

We have to find 12% of ? = 60

math percentage223

Shortcut Method to find the missing number in given expression of percent

We have to find 12% of ? = 60

We know that, if x% of y = m

Therefore, `y=(mxx100)/x`

Here in the given question, x=12, and m = 60 thus y=?

Therefore, `y=(60xx100)/12`

`y` = 5 × 100 = 500

Therefore, required number = 500 Answer

Alternate Method: Unitary Method

We have to find 12% of ? = 60

Let, ? = 100

12% of 100 = 12

Now,

12 is the 12% of 100

1 will be the 12% of `100/12`

60 will be 22% of `100/12xx60`

= 100 × 5 = 500

Thus, required number = 500 Answer

Question: (9) 30% of which number is equal to 25?

Solution:

We have to find 30% of ? = 25

math percentage224
math percentage225

Shortcut Method to find the missing number in given expression of percent

We have to find 30% of ? = 25

We know that, if x% of y = m

Therefore, `y=(mxx100)/x`

Here in the given question, x=30, and m = 25 thus y=?

Therefore, `y=(25xx100)/30`

`y=(25xx10)/3=250/3`

`y = 83\1/3`

Therefore, required number `= 83\1/3` or 83.333 Answer

Alternate Method: Unitary Method

We have to find 30% of ? = 25

Let, ? = 100

30% of 100 = 30

Now,

30 is the 30% of 100

1 will be the 30% of `100/30`

25 will be 30% of `100/30xx25`

`=(10xx25)3=83\1/3`

Thus, required number `= 83\1/3` or 83.333 Answer

Question: (10) 22% of which number is equal to 440?

Solution:

We have to find 22% of ? = 440

math percentage226

Shortcut Method to find the missing number in given expression of percent

We have to find 22% of ? = 440

We know that, if x% of y = m

Therefore, `y=(mxx100)/x`

Here in the given question, x=22, and m = 440 thus y=?

Therefore, `y=(440xx100)/22`

= 20 × 100 = 2000

Therefore, required number = 2000 Answer

Alternate Method: Unitary Method

We have to find 22% of ? = 440

Let, ? = 100

22% of 100 = 22

Now,

22 is the 22% of 100

1 will be the 22% of `100/22`

440 will be 22% of `100/22xx440`

= 100 × 20 = 2000

Thus, required number = 2000 Answer

MCQs Test

Math-home

  • Previous
  • Next

Reference:

Video liên quan