Please explain these few questions properly, step by step.

1)55% of students in a school are boys and the number of girls are 810. Find the total number of students and the number of girls.

2)Find a number which:

i) When increased by 10% becomes 77.

ii) When increased by 8% becomes 115.

3)Aditya's income is 20% less than that of Arnav. How much percent is Arnav's income more than Aditya's income?

4)The price of sugar increases by 20%. By what percentage should a housewife reduce consumption so that her expenditure does not increase?

5)At what rate percent will a sum of money double itself in 8 years?

Please explain properly! Thankyou.

Due to paucity of time, we are unable to solve all your queries. We are solving some of them.

Q1. The answer posted by @Shivangi64 for the first part is correct. Keep it up Shivangi. Continue the hard work.

Q3. Let Arnav`s income be 100.

So, Aditya`s income =

Arnav`s income is 20 more than that of Aditya`s =

Q4.

Expenditure = consumption × price

Let price of sugar be 100

Expenditure = consumption × 100

Consumption =

⇒expenditure = 100 × consumption 1

When the price of sugar increases by 20%,

the new price = 100 + 20%(100) = 100 + 20 = 120.

Expenditure = 120 × consumption 2

Since the consumption remains constant,

100 × consumption 1 = 120 × consumption 2

⇒ consumption 2 = consumption 1

Thus, the decrease in consumption =

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