If 60% of a number is added to 120, then the result is the number itself. 60% of this number is _______.
- AOption (a)
200
- BOption (b)
320
- COption (c)
180
- DOption (d)
300
View answer & explanationHide answer & explanation
Correct answer
180
Why this answer is correct
Shortcut Trick
If 60% of a number is added to 120 to get the number itself (100%), it means the added 120 represents the remaining 40%.
⇒ 40% of the number = 120
⇒ 1% of the number = 120 ÷ 40 = 3
⇒ 60% of the number = 3 × 60 = 180
∴ The correct answer is 180.
Alternate Method
Given: 60% of a number + 120 = the number.
Formula Used: Percentage value = (Percentage / 100) × Total Value
⇒ Let the number be x.
⇒ 60% of x + 120 = x
⇒ (60 ÷ 100) × x + 120 = x
⇒ 0.6x + 120 = x
⇒ x − 0.6x = 120
⇒ 0.4x = 120
⇒ x = 120 ÷ 0.4
⇒ x = 300
Now, we need to find 60% of this number:
⇒ 60% of 300 = (60 ÷ 100) × 300
⇒ 0.6 × 300 = 180
∴ The correct answer is 180.
Additional Information
Base Value Concept
In percentage problems, the original number is always treated as the base (100%). Any addition or subtraction is relative to this base.
Fractional Equivalents
Converting percentages to fractions simplifies calculation: 60% = 3/5 and 40% = 2/5. If 2/5 of a number is 120, then 3/5 is (120 ÷ 2) × 3 = 180.
Percentage Change Formula
The percentage increase or decrease is calculated as: (Change ÷ Original Value) × 100.

