Final answer:
The probability of exactly two coins landing heads up when three coins are tossed is 3/8.
Step-by-step explanation:
To find the probability that exactly two coins land heads up when three coins are tossed, we need to calculate the number of favorable outcomes and divide it by the total number of possible outcomes.
There are three possible outcomes where two coins land heads up: HHT, HTH, and THH. Therefore, the number of favorable outcomes is 3.
The total number of possible outcomes when three coins are tossed is 2 multiplied by itself three times, which equals 8.
So, the probability of exactly two coins landing heads up is 3/8.