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

To find 20% of 50% of 80:

First, find 50% of 80:

50% of 80 = (50/100) * 80 = 0.5 * 80 = 40

Then, find 20% of 40:

20% of 40 = (20/100) * 40 = 0.2 * 40 = 8

So, 20% of 50% of 80 is 8.

 Last updated on 12 NOV 2026

Explanation

Convert 1.15 into percentage:  

Multiply by 100:  

1.15 × 100 = 115%

 Last updated on 12 NOV 2026

Explanation

In the Tree of Rumour problem, one person passes the rumour to 2 other people every 5 minutes.

Therefore, the total number of people triples every 5 minutes.

0 minutes → 1 person

5 minutes → 3 persons

10 minutes → 9 persons

15 minutes → 27 persons

20 minutes → 81 persons

Using the formula:

3^20/5 =3^4 =81

 Last updated on 12 NOV 2026

Explanation

Let's calculate the population after 2 years:

Year 1:

Population = 50,000 + (4% of 50,000)

= 50,000 + 0.04 * 50,000

= 50,000 + 2,000

= 52,000

Year 2:

Population = 52,000 + (4% of 52,000)

= 52,000 + 0.04 * 52,000

= 52,000 + 2,080

= 54,080

The population after 2 years will be 54,080.

 Last updated on 12 NOV 2026