Explanation

Let original number = 100

Decreased by 12% = 100 - 12 = 88

Then increased by 15% = 88 + (15% of 88)

= 88 + (15*88/100)

= 88 + 13.2

= 101.2

Final value = 101.2

As percentage of original = 101.2%

Last verified on 24-10-2026

Explanation

Original number = 100

Increased by 20% = 100 + 20 = 120

Now we have to come back from 120 to 100

Decrease needed = 20

Percentage decrease = (Decrease / Increased Number) _ 100

= (20 / 120) _ 100

= (1 / 6) * 100

= 16.666...%

= 16⅔%

Last verified on 24-10-2026

Explanation

15% of 840 = 0.15 x 840 = 126

Last verified on 23-10-2026

Explanation

Increase = 100 − 80 = 20.

Percentage increase = (Increase ÷ Original number) × 100.

Percentage increase = (20 ÷ 80) × 100 = 25%.

Last verified on 23-10-2026

Explanation

Step 1: +30%

2,400 x 1.30 = 3,120

Step 2: -20%

3,120 x 0.80 = 2,496

Last verified on 22-10-2026

Explanation

Price becomes cheap, so you get 3 extra in $1.

Let old price = 100 cents

New price = 80 cents (20% less)

Old qty in $1 = let's say = x

New qty in $1 = x + 3

Money spent is same $1, so:

x _ 100 = (x+3) _ 80

100x = 80x + 240

20x = 240

x = 12

So old = 12 sharpeners in $1

New = 12+3 = 15 sharpeners in $1

For $5

Old = 12 x 5 = 60

New = 15 x 5 = 75

Last verified on 20-10-2026

Explanation

Total students = 50 + 40 + 30 + 20 = 140

Passed students:

Section 1: 50 _ 20% = 10

Section 2: 40 _ 15% = 6

Section 3: 30 _ 30% = 9

Section 4: 20 _ 50% = 10

Total passed = 10 + 6 + 9 + 10 = 35

Pass % of whole class = 35 / 140 * 100 = 25%

Failure % = 100% - 25% = 75%

Last verified on 20-10-2026

Explanation

Single discount = 100 - (100 - D1)_(100 - D2)/100

= 100 - (100 - 15)_(100 - 30)/100

= 100 - 85 * 70 / 100

= 100 - 5950 / 100

= 100 - 59.5

= 40.5%

Last verified on 20-10-2026

Explanation

Let number = x

Correct = x _ 2/3

Wrong = x _ 3/2

Error = Wrong - Correct = x _ 3/2 - x _ 2/3 = x _ 5/6

Percentage Error = Error / Wrong _ 100

Percentage Error = (x _ 5/6) / (x _ 3/2) _ 100

Percentage Error = 5/6 _ 2/3 _ 100

Percentage Error = 10/18 _ 100

Percentage Error = 5/9 _ 100

Percentage Error = 55.55 percent

Last verified on 20-10-2026

Explanation

Boys passed = 60% of 1200 = 720

Girls passed = 40% of 800 = 320

Total appeared = 1200 + 800 = 2000

Total passed = 720 + 320 = 1040

Total failed = 2000 - 1040 = 960

% failed = (960 / 2000) x 100 = 48%

Last verified on 20-10-2026