Ok, so if everyone needs 1 cup then fine how many 24's go in to 60. 24, 48, 62. Even though it is over the desired amount it is better than under serving. So now you know you need 3 packages of cups.
As for napkins, do the same but with 16's into 60. 16, 32, 48, 64. Moreover you need 4 packages of napkins.
hope this helped
