Trong bài thi có 2 câu hỏi độc lập. Biết sắc xuất để trả lời đúng câu hỏi của sinh viên là 0,7 và 0,9. Tính xắc suất đế sinh viên trả lời đúng nhất 1 câu

A. 127 cm^2 b. 144.5 cm^2 c. 172 cm^2 d. 50 cm^2

Atheater wants to build movable steps that they can use to go on and off the stage. they want the steps to have enough space inside so they can also be used to store props. how much space is inside the steps?

Money off coupons have been circulated to 300 households. only 2/5 of these were redeemed (used) in the local supermarket to get a free shampoo. what fraction of coupons were unused? (ps: write how you got the answer)