Lớp 10A có 40 học sinh trong đó có 10 bạn học sinh giỏi Toán, 15 bạn học sinh giỏi Lý và 19 bạn không giỏi môn học nào trong hai môn Toán, Lý. Hỏi lớp 10A có bao nhiêu bạn học sinh vừa giỏi Toán vừa giỏi Lý?
Lớp 10A có 40 học sinh trong đó có 10 bạn học sinh giỏi Toán, 15 bạn học sinh giỏi Lý và 19 bạn không giỏi môn học nào trong hai môn Toán, Lý. Hỏi lớp 10A có bao nhiêu bạn học sinh vừa giỏi Toán vừa giỏi Lý?
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Ta có: $|A| = 10$, $|B| = 15$. Số học sinh không giỏi môn nào là 19.
Số học sinh giỏi ít nhất một trong hai môn là: $40 - 19 = 21$.
Theo công thức $|A \cup B| = |A| + |B| - |A \cap B|$, ta có:
$21 = 10 + 15 - |A \cap B|$
$|A \cap B| = 10 + 15 - 21 = 4$.
Vậy, số học sinh vừa giỏi Toán vừa giỏi Lý là 4.
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According to the passage, how has coronavirus crisis affected 20 percent of college students?