The time spent by a customer at a checkout counter has mean 4 minutes and standard deviation 2 minutes. a) What is the probability that the total time taken by a random sample of 50 customers is less than 180 minutes? b) Find the 30th percentile of the total time taken by 50 customers.

step-by-step explanation:

ok so im not 100% sure but you would start by adding 5.1t and 1.9t beacuse they have the same variable. that is 7t.   then add -3.6 + 1.2 which is -2.4

so then keep that as -2.4 + 7t. i apologize if this is incorrect. best luck on your test < 3

94

step-by-step explanation:

average the numbers and use a variable to figure out the minimum to get a 90.

(79+94+91+92+x)/5=90

x = 94

what is the answer to this