Help pls help me on these Geometry proofs

Apackage of bacon holds 15 strips of bacon. the pancake house uses 17 packages of bacon in the morning and 21 packages in the afternoon. how many more strips were used in the afternoon than the morning?

When 142 is added to a number the result is 64 more times the number my options are 35 37 39 41

The standard deviation for a set of data is 5.5. the mean is 265. what is the margin of error?