190 students take midterms. 178 of them pass the Math exam, 181 pass the Chinese exam and 174 pass the English exam. Then at least students pass all the 3 exams.

Since we want the least amount, we need to avoid repetitions of counting those who fail the 3 exams. That is, when the numbers do not contains each other, the number of students pass the exams is the least.

190 − 178 = 12 students fail the Math exam.

190 − 181 = 9 students fail the Chinese exam.

190 − 174 = 16 students fail the English exam.

Then at most 12 + 9 + 16 = 37 coins fail the exams. So at least 190 − 37 = 153 students pass all the exams.