Final answer:
The probability that both coins flipped will not land on heads is 75%, considering the sample space with four equally likely outcomes: HH, HT, TH, and TT, where three out of four outcomes are favorable.
Step-by-step explanation:
When flipping two coins, the probability of both coins not landing on heads involves considering all the possible outcomes. The sample space for flipping two fair coins is {HH, HT, TH, TT}, where 'H' represents heads and 'T' represents tails. Out of these four outcomes, three do not result in both coins landing on heads: HT (first coin heads, second coin tails), TH (first coin tails, second coin heads), and TT (both coins tails).
Each outcome has an equal chance of occurring, which is 1/4 or 25%. Therefore, to find the probability that both coins will not land on heads, we add the probabilities of the three favorable outcomes: 1/4 + 1/4 + 1/4 = 3/4 or 75%. So, the probability that both coins will not land on heads is 75%.