5 laps / 10 minutes
Ratio
Lap: minute
5: 10
it is four times the number of laps therefore four times the time
20: 10*4
20: 40
or
using the ratio
5 laps / 10 minutes ot 10 minutes/ 5 laps
20 laps* 10/ 5 = 200/5 = 40
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Answer
it will take her 40 minutes