Jeremiah's fountain holds 15 sallons of water when completely full. He has some water in the fountain and added 2.6 gallons of water to fill it completely.
How many gallons of water were in the fountain before Jeremiah added some?

The table below shows the approximate masses of a dust particle and a grain of pollen. dust particle 0.000000778 g grain of pollen 0.00000000155 g the mass of a dust particle can be estimated and written in the form a × 10^b, where a = 8 and b = the mass of a grain of pollen can be estimated and written in the form a × 10^b, where a = 2 and b = based on the estimates, the mass of a dust particle is approximately blank times larger than the mass of a grain of pollen.