Question

A number is increased by x% and then decreased by 10%. If the net effect on a number is a 5% increase then find the value of x%

1. 20%
2. \(16\frac{{2}}{{3}}\)% 
3. \(38\frac{1}{{19}}\)%
4. 17%

Answer 1

Correct Answer - Option 2 : \(16\frac{{2}}{{3}}\)% 

Given:

Percent decrease = 10%

Net effect = 5% increase

Formula used:

Net effect = x + y + (x × y)/100

Calculations:

Here, y = - 10%

⇒ 5 = x – 10 – (5x/100))

⇒ 5 + (10x/100) = x – 10

⇒ 500 + 10x = 100x – 1000

⇒ 90x = 1500

⇒ x = 1500/90

⇒ x = (500/30)%

⇒ x = \(16\frac{{2}}{{3}}\)%

∴ The value of x is \(16\frac{{2}}{{3}}\)%