He lengths of a particular animal's pregnancies are approximately normally distributed, with mean muequals252 days and standard deviation sigmaequals20 days. (a) What proportion of pregnancies lasts more than 262 days? (b) What proportion of pregnancies lasts between 227 and 257 days? (c) What is the probability that a randomly selected pregnancy lasts no more than 237 days? (d) A "very preterm" baby is one whose gestation period is less than 202 days. Are very preterm babies unusual?

Step-by-step explanation:

Let X be the lengths of a particular animal's pregnancies

X is N(252, 20)

(a) What proportion of pregnancies lasts more than 262 days?

(b) What proportion of pregnancies lasts between 227 and 257 days?

(c) What is the probability that a randomly selected pregnancy lasts no more than 237 days?

P(X<237) = 0.2266

(d) A "very preterm" baby is one whose gestation period is less than 202 days. Are very preterm babies unusual?

Yes very unusual since probability is very near to 0.

i used to know how to do this in 7th but i forget easily

step-by-step explanation:

70

step-by-step explanation:

2*5=10

4*15=60

60+10=

70