20 large cakes will require the equivalent of 10 helpers working for one hour. 700 small cakes will require the equivalent of 20 helpers working for one hour. This means if only one hour were available we would need 30 helpers. But since three hours are available we can use 10 helpers.

If the price is reduced by 15 %, then the new price will be 0.85D

If this new price is further reduced by 10%, the discounted price will be 0.9 x 0.85D = 0.765D

              Men               Women

              600x               400x

      Total engineers = 480x

      Male engineers = 480x X 0.66 = 320

   Women who are Engineers  = 160x 

  Women are not Engineers  = 400x - 160x = 240x

 Required percentage = 240 400 x 100 = 60%

Given, 

25% of three-seventh of 26% of a number is 145.5

Let the required number be 'N'

i.e,  25 100 x 3 7 x 26 100 x N = 145 . 5

N =  145 . 5 x 7 x 10000 75 x 26

=> N = 5223.07

Given that to find 15 of 80

=> What % of 80 is 15

Let it be 'p'

=> p% of 80 = 15

=>  $$\begin{gathered} p x 80 100 = 15 \\ ? p = 15 x 100 80 \\ ? p = 1500 80 = 18 . 75 \end{gathered}$$

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 = 

$$\begin{gathered} 16 = p × 225 100 \\ p = 1600 225 = 7 . 1111 \end{gathered}$$

Let X be the total amount with Ramesh

Given 28% of X = Cash remaining

=> Amount spent = 72% of X = 38460 + 24468 = 62928

=> 72% of X = 62928

=>  X = ?

=> X = 87400

Here, k = 7 and l = 28
Therefore, first number = k lx100 % of second number = 7/28 x 100% of second number = 25% of second number.

Let the total population be 'P'

P x (96/100) = 23040

P = 240 * 100

P = 24000.

Let the required number be 'p'

36 of what number is 18 implies 36% of p = 18

=> 36 x p/100 = 18

=> p = 1800/36

=> p = 50.

Hence, 36% of 50 is 18.