Answer:
27 years old
Step-by-step explanation:
Let Alvin's age be x and Elga's age is y:
y - x = 15
x + y = 27
2y = 42 (use elimination method)
y = 21
x = 6 (plug it back into either equation)
Therefore Alvin is 6 and Elga is 27
200 divided by 18 = 11.1
This means that the minimum number of gallons that she will need is 11.1.
the first one is left and the second one is up
