Eric purchased a box of 72 nails to build a shelf but did not use all of the nails. The ratio of nails he used to the nails he did not use is 7 to 2. How many nails were left from the box of nails Eric bought?

Answer:The number of nails were left from the box of nails Eric bought is 16 .Step-by-step explanation:Given as :The total number of nails in the box = 72The ratio of used nails to the unused nails = 7 : 2Let The number of used nails = 7 xAnd The number of unused nails = 2 xNow, According to questionThe total number of nails in the box = 72Or, The number of used nails +  The number of unused nails = 72or, 7 x + 2 x = 72or, 9 x = 72∴ x = [tex]\frac{72}{9}[/tex]I.e x = 8So, The number of used nails = 7 × 8 = 56And  The number of unused nails = 2 × 8 = 16Now, The nails left in the box = 72 - The number of used nailsOr, The nails left in the box = 72 - 56Or, The nails left in the box = 16Hence The number of nails were left from the box of nails Eric bought is 16 . Answer