You need to integrate to go from the rate of air flow back to the original equation of the volume of air flow. You may be confused by the fact that they didn't write the rate as a differentiation and instead wrote it as R as it's a common misconception in these types of exam questions but yeah no the R represents the rate and not the original base equation, you integrate to find that base equation. if you have any other question or are still confused I'm happy to help
You need to integrate to go from the rate of air flow back to the original equation of the volume of air flow. You may be confused by the fact that they didn't write the rate as a differentiation and instead wrote it as R as it's a common misconception in these types of exam questions but yeah no the R represents the rate and not the original base equation, you integrate to find that base equation. if you have any other question or are still confused I'm happy to help