Questions

Two series alternate here, with every third number following a different pattern.
In the main series, 4 is added to each number to arrive the next.
In alternate series, 5 is subtracted from each number t arrive the next number.
Here in the main series 
3 + 4 = 7
7 + 4 = 11
11 + 4 = 15
15 + 4 = 19

In alternate series 
24 - 5 = 19
19 - 5 = 14...

Let the required number of bottles be x.

More weavers, More mats (Direct Proportion)

More days, More mats (Direct Proportion)

$$\begin{gathered} Wavers 4:8 \\ Days 4:8 \end{gathered}$$  :: 4:x

 4 x 4 x x = 8 x 8 x 4

=> x= 8*8*44*4

=>  x = 16.

It is ABACUS.

Words formed are as below 

BUS
CAB
CUB
US

To produce controlled energy i.e energy at a controlled or steady rate, the number of fissions per second must be controlled and maintained at that rate. Excess neutrons should be absorbed by control roads like cadmium.

10C5 x 28C1 x 10C6 = 7266