If one needs to score 34% to pass a test, the pass marks out of 40 would be:

 

Given that to find 15 of 80

=> What % of 80 is 15

Let it be 'p'

=> p% of 80 = 15

=> $$\begin{gathered} p x 80100 = 15 \\ ⇒p = 15 x 10080 \\ ⇒p = 150080 = 18.75 \end{gathered}$$

Therefore, 15 is 18.75% of 80 => 18.75% of 80 = 15

Example::

Now, in the similar way we can find 15% of 80 =?

=> 15x80/100 = p

=> p = 4 x 3 = 12

Therefore, 15% of 80 = 12

16 of 225 is = 

$$\begin{gathered} 16 = p × 225100 \\ p = 1600225 = 7.1111 \end{gathered}$$

Ratio of girls and boys = 100% : 75% = 4:3

Difference is 1 unit = 35

So, 3 units = 35 x 3 = 105

If 20% absent, that’s mean 80% present.

So, present boys = 80% of 105 = 80×105100 = 84

1st day the girl read = 40%

2nd day she read = 34 %

Remaining percentage of book = 100% - (40% +34%) = 26%

But given last two days she read equal number of pages

=> Each day she read 26%/2 = 13%

Last day she read 52 pages = 13%

13% = 52

1% = 4

=> 100% = 400

Total pages in the book is 400.

Let the cost price of the article be 'P'

Then from given data,

$$\begin{gathered} P + 28P100 = 4544 \\ => 128P = 454400 \\ => P = 3550 \end{gathered}$$

Hence, the cost price of the article = P = Rs. 3550

25% of 25% means

25/100 of 25/100

i.e, 1/4 of 1/4

or in other words 1/4 x 1/4=1/16

Hence, the answer is 1/16 = 0.0625.

Let his monthly salary be 'P'

20% on children's education = 20P100 = P5

50% on food and transport = 50P100 = P2

1000 on rent

=> $$\begin{gathered} P - P5 - P2 - 1000 = 2000 \\ => 3P = 30000 \\ => P = 10000 \end{gathered}$$

Therefore, his monthly salary = Rs. 10,000

Given 56% of 225 + 20% of 150 = ? - 109

we know that a% of b = b% of a

Now,

225% of 56 + 20% of 150 = ? - 109

200% of 56 + 25% of 56 + 20% of 150 = ? - 109

112 + 14 + 30 = ? - 109

? = 112 + 14 + 30 + 109

? = 264