10x + 17 use PEMDAS (Parenthesis, Exponents, Multiplication, Division, Addition, Subtraction)
Answer: 8 
hours
Step-by-step explanation:
Let x represent the time it takes if both are used.
The unit time it takes to fill the pool using the first house is 1/20 and also the unit time it takes to fill the pool using the second house is 1/16 , therefore:
1/16 + 1/20 = 1/x
= 
=
Therefore
x = 
Therefore, it takes 8 hours using both houses
Answer:13 students
Step-by-step explanation: 6+7=13
Answer:
120 dollars
Step-by-step explanation:
6 hours per day, for 2 days, leads to a total of 12 hours (2*6 = 12)
If it takes 2 gallons of gas to run the boat for 1 hour, then it will take 24 gallons to run for 12 hours. We can see this if we have the ratio below
2 gallons: 1 hour
12*(2 gallons): 12*(1 hour) .... multiply both sides by 12
24 gallons: 12 hours
Now multiply this gallon count (24) by the cost per gallon ($5) and we get to 5*24 = 120
