GreenlightTestPrep wrote:
Barrel A and barrel B have a combined capacity of 360 liters. If barrel B's capacity is 30 liters greater than twice barrel A's capacity, what is the capacity of barrel A?
Answer:
APPROACH #1: 1 variable Let x = barrel A's capacity (I chose this quantity since the questions is explicitly asking for this value)
So, 360 - x = barrel B's capacity (since the two barrels have a combined capacity of 360 liters)
If barrel B's capacity is 30 liters greater than twice barrel A's capacity, we can write: 360 - x = 2x + 30
Add x to both sides: 360 = 3x + 30
Subtract 30 from both sides: 330 = 3x
Solve: x = 110
Answer: 110
APPROACH #2: 2 variables Let A = barrel A's capacity
Let B = barrel B's capacity
Since they have a combined capacity of 360 liters, we can write:
A + B = 360 Since barrel B's capacity is 30 liters greater than twice barrel A's capacity, we can write:
B = 2A + 30 We now have the following system of equations:
A + B = 360 B = 2A + 30Solve for A to get: A = 110
Answer: 110