Question

A researcher is selecting lab rats for her experiment. She assigns each rat a number and picks numbers out of a hat while blindfolded. The pool of rats from which she is drawing participants is composed of the following: 23 male albino rats 21 male spotted rats 35 female albino rats 11 female spotted rats If she reaches into the hat twice, what is the probability of choosing a male albino rat and then either a female albino rat or a male spotted rat

Answer 1

Answer: $\dfrac{76}{89}$

Step-by-step explanation:

The pool of rats from which the researcher is drawing participants is composed of the following:

23 male albino rats

21 male spotted rats

35 female albino rats

11 female spotted rats

Total rats = 23+21+35+11 =90

$P(male\ albino)=\dfrac{23}{90}$

After drawing first rat , total rats remained = 89

$P(\text{either a female albino rat or a male spotted rat})=\dfrac{35+21}{89}=\dfrac{76}{89}$

The probability of choosing a male albino rat and then either a female albino rat or a male spotted rat = $\dfrac{76}{89}$