Maths Set Theory Puzzle

In a school, there are four subjects. Seventy percent of students study English, seventy five percent of students study Science, eighty five percent of students study Mathematics and eighty percent of students study Spanish.

Can you calculate the percentage of students that study all four subjects?




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The inventor of the Rubik’s Cube didn’t realize he’d built a puzzle until he scrambled it the first time and tried to restore it.