After the cut he earns 80% of his original income. To rise these 80% to a 100% again he has to add 20%. The percentage is

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Let s denote the distance from home to school. Then the first elapsed time is:3. a boy walks from his home to school at 6kmph . walks back at 2 kmph. avg. speed=?

and

The boy walks the distance twice. Then the average speed is: