Of the 90 gallons a average person uses a day,30% is used out doors. Mason wants to know how much water is used indoors

63 gallons.

Step-by-step explanation:

If 30% of water is used outdoors, that leaves 70% to be used indoors. Since an average person uses 90 gallons, all we need to do is fine 70% of 90 gallons. To do this, we have to multiply 90 by 0.7:

90 * 0.7 = 63

In conclusion, 63 gallons of water are used indoors.

the answer is a if my teacher taught me correct