Question 252380
We know he must use at least one 8 cent stamp to get the 3 of 153
that leaves us with 145
8*15=120
anything more than that leaves odd amounts that don't meet our criteria of 0 or 5

we need an amount that ends in 5 or 0 so that we can use the 5 cent stamps to complete
so 16 8 cent stamps and 5 5 cent stamps is the smallest number of stamps he can use to mail his package