there are 89 people that own pets . 15 people own only dogs , 10 people own only cats , 5 people own only cats and dogs , 3 people own cats , dogs and snakes . how many total snakes are there ?
"lets assign variables to all the areas in venn diagram of three . three different units are dog , cat , snake = total = 89 only dog = d = 15 only cat = c = 10 only snake = s exactly dog and cat = 5 exactly dog and snake = x exactly cat and snake = y all three = 3 so 89 = 15 + 10 + 5 + 3 + x + y + s we need to know total snakes = x + y + s + 3 = 59 answer : d"
add(subtract(89, add(add(add(15, 10), 5), 3)), 3)