Chocolate bars are sold in packages of four or nine only. If Mark bought 97 chocolate bars exactly, what could be the number of large packs Mark bought?
Pick one
A) 3	B) 4	C) 8	D) 9	E) 13
Let number of packs of four = f   let number of packs of nine = n   4f + 9n = 97   Now , we need to test for values of n.   Since sum 97 is odd and 4f will always be even , n can't be even .   Now , we can test for values e = 2 , 4 and 6   4*4 + 9*9 = 16 + 81= 
<gadget id="calculator">16 + 81</gadget>
<output>97</output>
97   Answer 9
<result>D</result>
Chocolate bars are sold in packages of four or nine only. If Mark bought 97 chocolate bars exactly, what could be the number of large packs Mark bought?