Pls help me with my homework I need help

Question

The cold water faucet can fill the tub in one half-hour. The hot water faucet can fill the tub in one hour how long will it take to fill the tub with both faucets running? Justify your answer

Answer 1

Let's assume the tub holds 100 gallons (This is strictly arbitrary... could use any reasonable value)

Then, to fill the tub in half an hour means 100 gallons/.5 hour = 200 gallons/hour

Then, to fill the tub in one hour means the rate is 100 gallons/ hour

Working together, the rate is 300 gallons/hour.

So, 100 gallons/(300 gallons/hour) = 1/3 hour to fill the tub if both run together