Her oldest wants 2 strings cheeses a day for 5 days so 2*5 = <<2*5=10>>10 string cheeses
Her youngest wants 1 string cheese a day for 5 days so 1*5 = <<1*5=5>>5 string cheeses
Together they want 10+5= <<10+5=15>>15 string cheeses a week
Over 4 weeks, her kids will eat 15 string cheeses so 4*15 = <<15*4=60>>60 string cheeses
The bags have 30 per pack and she needs 60 so 60/30 = <<60/30=2>>2 packs of string cheese
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