Francis' family has 2 ukuleles, 4 guitars, and a certain number of violins. Each ukulele has 4 strings. Each guitar has 6 strings. Each violin has 4 strings. If the total number of strings among the ukuleles, guitars, and violins is 40 strings, how many violins does Francis' family have? Let's be accurate as possible.
From the ukuleles, there are 2 * 4 = 8 strings. From the guitars, there are 4 * 6 = 24 strings. From the violins, there are 40 - 8 - 24 = 8 strings. The total number of violins Francis' family has is 8 / 4 = 2 violins.
The answer: 2.