There are four 50 gallons water tanks at a farm. each tank has had 4/5 of the water used. how much water is left in the tank all together

40 gallons of water

Step-by-step explanation:

50 gallons times 4 tanks is 200 gallons. 4/5 of 50 is 40 so you subtract 40 from 50. That makes 10 for 1 tank. When you multiply that by 4 tanks, it makes 40 gallons.

Step-by-step explanation:

When multiplying 2 numbers with the same base number, we can directly add their indices.

For example, 2¹ * 2³ = 2^(1 + 3) = 2⁴.

Therefore 7³ * 7^? = 7^(3 + ?) = 7¹⁴.

=> 3 + ? = 14, ? = 11.

The blank should be filled with 11.