1 7 x 1 2 x 1 9 . 5 x 1 2 x 2660 = 2660 266 = 10

$$\begin{gathered} 7 8 x 448 + 6 7 x 3374 \\ = > 392 + 2892 \\ = > 3284 \end{gathered}$$

142 x 142 x 1 1260 . 25

=>  142 x 142 x 1 35 . 5 = 568

We know that 

$$\begin{gathered} 40 % = 40 100 = 2 5 \\ ? 2 5 x 24 4 x ? = 48 \\ ? = 48 x 5 x 4 2 x 24 = 20 \end{gathered}$$

Given fraction is 5 (2/7) - 3 (1/14) - 2 (1/14) - 1 (1/7) = ? + 3 (1/17) 

It can be written as 

(5 - 3 - 2 - 1) + (2/7 - 1/14 - 1/14 - 1/7) = ? +  3 (1/17) 

-1 + 0 - 3 (1/17) = ?

=> ? = -4 (1/17)

Let the number of males be 'M'
Let the number of females be 'F'
From the given conditions,
(F-15)=2M.....(i)
F=5(M-45).....(ii)
By solving the equations (1) & (2) we get M = 80
Then substitute M = 80 in (1)
F = 2M + 15
F = 2 x 80 + 15
=> F = 175
Therefore, number of males = 80 and females = 175 in the party.

Monday + Tuesday + Wednesday = 37 x 3 -----------(1)
Tuesday + Wednesday + Thursday = 34 x 3---------(2)
Thursday = 4/5 of Monday ------------------(3)
subtract eqn (1) from (2) we get,
Thursday - Monday = -9
=> Monday - Thursday = 9.......(4)
From (3) & (4), we get

So,Thursday = 36 C

According to BODMAS rule,

After multiplication only, addition is done.

Hence,

5 + 2 x 10 = 5 + 20 = 25.