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