Aradio program gives concert tickets to the fourth caller with the right answer to a question. of the people who call, 25% know the answer. phone calls are independent of one another. the random variable nr indicates the number of phone calls taken when the rth correct answer arrives. (if the fourth correct answer arrives on the eighth call, then n4 = ) what is the pmf of n1, the number of phone calls needed to obtain the first correct answer? (b) what is e[n1], the expected number of phone calls needed to obtain the first correct answer? (c) what is the pmf of n4, the number of phone calls needed to obtain the fourth correct answer? (d) what is e[n4].

water molecules will move from the side of higher water concentration to the side of lower concentration until both solutions are isotonic. at this point, equilibrium is reached. in an isotonic solution, the flow of water in and out of the cell is happening at the same rate.

hope this < 3

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step-by-step explanation:

the 8 in 8,420 is in the thousands place so it's value is 8 thousand.

the 8 in 6,870 is in the hundreds place so it's value is 8 hundred.

divide 8000 by 800 to find the answer:

8000 / 800 = 10

the 8 in 8,420 is 10 times greater than the 8 in 6,870

320ft

step-by-step explanation:

120 divided by 3 equals 40

40 times 4=160

160 times 2=320