Of 350 students polled, some have a cat, some have a dog, and some have both. One hundred seventy-five students have a cat and 140 have both types of pets. How many students have a dog only? Explain.
I believe the answer was:
175; Since 175 have a cat or a cat and dog, then the number that have a dog only is 350 − 175 = 175.
But I just needed to check