In a group of 36 pupils, 10 play the flute only. 15 play the piano only. 4 play neither instrument. A student is selected at random. What is the probability the student plays both instruments?

Rockwell hardness of pins of a certain type is known to have a mean value of 50 and a standard deviation of 1.1. (round your answers to four decimal places.) (a) if the distribution is normal, what is the probability that the sample mean hardness for a random sample of 8 pins is at least 51?

Can someone check if i did this correct. it’s number 4 if you’re wondering.

Rewrite the following quadratic functions in intercept or factored form. show your work. f(x) = 3x^2 - 12