Ashley paid 5 dollars for 1 notebook and 1 pencil. If both prices were integers, how many pencils did Ashley buy if she paid 93 dollars for the pencils and for 15 notebooks?	Select the correct option
A) 6. B) 16. C) 18 D) 21 E) 26
5 = 1P + 1 N   93 = XP + 15N, where X is the number of pencils   Possible prices for 1P &amp; 1N (integers):   N = 1 P = 4 then 15N = 15, 4X = 93 - 15= 
<gadget id="calculator">93 - 15</gadget>
<output>78</output>
78, X= 19.5 (not an integer)   N = 2 P = 3 then 15N = 30, 3X = 93 - 30= 
<gadget id="calculator">93 - 30</gadget>
<output>63</output>
63, X= 21 (the answer we were looking for, no need to continue calculations)   N = 3 P = 2   N = 4 P =1   Answer: 21
<result>D</result>
Ashley paid 5 dollars for 1 notebook and 1 pencil. If both prices were integers, how many pencils did Ashley buy if she paid 93 dollars for the pencils and for 15 notebooks?