You flip 2 coins. what is the probability that one coin will land on heads and one coin will land on tails? createa sample space of outcomes.

HH, TT, HT, TH
2/4=1/2=50%

You have two coins. You want one to have tails, and one to have heads. This is a 50% (1/2) chance for either heads or tails on ONE coin. However, if you want the order you are asked, you have a 1/2 chance that one lands on head and one lands of tail. The reason is this:

There is only 4 different ways it would be resulted:
T= Tails
H = heads
H H, T H, H T or T T

Only T H and H T out of the 4 is valid, therefore 1/2 chance.

Yes. there is a constant ratio of number of calories to gram of protein.12/3=24/4=32/8=44/11=4