My project uses a arduino, 3 flame sensors, 2 motors dc, 1water pump 12v. i use a power bank supplying 5v 1a 10000mah. how long will it last.
1a = 1000ma 
Dc motors 12v - no load 60ma load- 300ma each. pump 100a - 500ma. motor drives has normal size green led.
motors and pump run all time.(untill battety goes down) + 3 flame sensors ir. no more components. i dont no current of ir fame sensors. thats all. all components on all time.
There are so many variables, it is hard to say. If you want a wild guess, I would guess 10 minutes to 3 hours.
The best answer will be when you time it. ( do it three times ).
Let us know what the results are.
How you supply the 12v to motors and pump from a 5v power bank?
Running all time with load or no load?
This looks like a good case for some empirical testing. Build your circuit, run it until it dies several times. Then please report your data back here.
Dasaradh:
Dc motors 12v - no load 60ma load- 300ma each. pump 100a - 500ma. motor drives has normal size green led.
2 DC motors = 600ma
1 pump = 500ma
your load for these 3 parts is 1,100ma or 1.1 amps
your power supply is 10 ah
based on pure numbers and simple math, as long as 9 hours.
but if your motors or pump uses more or less, then your supply will last longer, or shorter.
what you did not tell us was what type of batteries. each type of battery will have a curve as power is used.
as the end of the power is getting closer, the voltage will drop. as the voltage drops, your power use changes.
Just give it a try. Test it. What are your results?