Carol H. answered • 09/14/18

Masters' Degree in Mathematics with 35 years of Teaching Experience

**Let x = the number of 400 MB flash drives John bought**

**Let y = the number of 300 MB flash drives John bought**

**x + y = 14 x = 14 - y**

**400x + 300y = 4700**

**400(14 - y) + 300y = 4700**

**5600 - 400y + 300y = 4700**

**-100y = -900**

**y = 9 flash drives**