Hello!
Robin can clean 72 rooms in 6 days. How many rooms can Robin clean in 9 days?
We have a proportional magnitude (directly proportional), if we increase the number of days for cleaning, obviously we will have more rooms cleaned, then:
clean rooms __________ days
72 ----------------------------------- 6
y ------------------------------------- 9

multiply the means by the extremes




Answer:
108 clean rooms in 9 days
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I Hope this helps, greetings ... Dexteright02! =)