Can someone explain how you do this and not only give me the answer?

How is working backward similar to solving an equation?

When a valve is open 281 gallons of water go through it in one hour the number of gallons that would go through in 94 hours is

Aplane is flying at 32,500 feet. it needs to rise to 36,000 feet in two stages.• in stage 1, it rises 5% of its initial altitude of 32,500 feet.• in stage 2, it rises at a rate of 125 feet per minute.how many minutes does it take for the plane to rise during stage 2?