Answer :
Answer:
1 hour
Step-by-step explanation:
First of all you multiply 20 by 5 to calculate the distance he travelled, which is 100 then you add 5 to 20 to get the new speed which is 25 finally you divide his distance by the new speed 100/25 which is 4 and as 5-4=1 he would have saved 1 hour.
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