1 Para crear una prueba, un profesor tiene un banco de 50 preguntas. Si de ellas escogerá 20. ¿de cuántas formas puede crear la prueba? \( =50 \) \( =20 \)

19. A student at a certain college has \( 60 \% \) chance of passing an examination at the first attempt. Each time a student fails and repeats the examination; his chances of passing are increased by \( 15 \% \). Calculate the probability that a student in the college passes an examination at the second or at the third attempt. [3008 marks)

A single die is rolled twice. Find the probability of rolling a 3 the first time and a 2 the second time. Find the probability of rolling a 3 the first time and a 2 the second time.

The reading speed of second grade students in a large city is approximately normal, with a mean of 88 words per minute (wpm) and a standard deviation of 10 wpm. Cor (a) What is the probability a randomly selected student in the city will read more than 94 words per minute? The probability is (Round to four decimal places as needed.)

A single die is rolled twice. Find the probability of rolling an even number the first time and a number greater than 4 the second time. Find the probability of rolling an even number the first time and a number greater than 4 the second time. \( \square \) (Type an integer or a simplified fraction.)

fair coin is tossed three times in succession. The set of equally likely outcomes is \( \{\mathrm{HHH}, \mathrm{HHT}, \mathrm{HTH}, \mathrm{THH}, \mathrm{HTT}, \mathrm{THT}, \mathrm{TH}, \mathrm{TTT}\} \). Find the probability of getting exactly e head.