A professor of cognitive psychology is interested in the percent accuracy on this memory encoding task among college students. She measures the percent accuracy for 36 randomly selected students. The professor knows that the distribution of scores is normal, but she does not know that the true average percent accuracy on this memory encoding task among college students is 0.793 percent correct with a standard deviation of 0.114 percent correct.

1- is the product of two rational numbers irrational or rational? first, make a hypothesis by multiplying two rational numbers. then, use variables such as x=a/b and y=c/d and the closure property of integers to prove your hypothesis. 2- what do you think the product of a nonzero rational number and an irrational number is? is it rational or irrational? make use of variables, the closure property of integers, and possibly a proof by contradiction to prove your hypothesis. 3- why do we have to specify that the rational number must be nonzero when we determine what the product of a nonzero rational number and an irrational number is? if the rational number were 0, would it give us the same result we found in part b?

Aspacecraft can attain a stable orbit 300 kilometers above earth if it reaches a velocity of 7.7 kilometers per second. the formula for a rocket's maximum velocity v in kilometers per second is vequalsminus0.0098tplusc ln upper r, where t is the firing time in seconds, c is the velocity of the exhaust in kilometers per second, and r is the ratio of the mass of the rocket filled with fuel to the mass of the rocket without fuel. find the velocity of a spacecraft whose booster rocket has a mass ratio of 20, an exhaust velocity of 2.1 km/s, and a firing time of 15 s. can the spacecraft achieve a stable orbit 300 km above earth?

The thickness of photoresist applied to wafers in semiconductor manufacturing at a particular location on the wafer is uniformly distributed between 0.2070 and 0.2171 micrometers.(a) determine the proportion of wafers that exceeds 0.2125 micrometers of photoresist thickness. (round your answer to 3 decimal places.)enter your answer in accordance to the item a) of the question statement(b) determine the mean of x. (round your answer to 4 decimal places.)enter your answer in accordance to the item b) of the question statement micrometers(c) determine the variance of x. (round your answer to 8 decimal places.)enter your answer in accordance to the item c) of the question statement micrometers2