The biologist should use a block design because the different types of bacteria may respond differently to the treatments.
All you wanna do is get 'y' by itself so you divide 80 by -5 and you get -16 as the answer
The answer is 8/12 because you find a common denominator which is 12 so if you multiply 4×3 on the bottom you do it to the top which gives you 3 so 11-3 is 8. 11/12 - 3/12
First, find the probability of picking one 9. There are four nines in a deck of 52, so the probability is 4/52, which is 1/13.
The probability of picking a 9 the second time is 1/17, because if a 9 was picked the first time, then there are three 9s left and 51 cards left in total.
To find the probability of both events happening, multiply the individual probabilities together:
(1/13)(1/17)
The probability that both cards picked will be 9s is 1/221.
