A survey was taken of 100 college freshman. Forty of then were majoring in Mathematics, 30 of them were majoring...

A survey was taken of 100 college freshman. Forty of then were majoring in Mathematics, 30 of them were majoring in English, 20 were majoring in science, 7 had a double major of mathematics and English, and none had a double major with science . How many students had majors other than mathematics, English or science?