The box she ship in has the volume of 1440 cubic inch. The cookie box is 60 cubic inch, so if you divided 1440 into 60, you would get 24. So. she can fit 24 cookie boxes into the box to be shipped.
'One third' as a decimal is 1 ÷ 3 = 0.333333..... ⇒ The decimal is recurring
'One fifth' as decimal is 1 ÷ 5 = 0.2 ⇒ The decimal terminates at the tenth value
'One seventh' as decimal 1 ÷ 7 = 0.142857142857.... ⇒ The decimal is recurring for every digit between 1 and 7
'One ninth' as decimal 1 ÷ 9 = 0.111111.... ⇒ The decimal is recurring
Answer: one fifth