Regarding information on the internet, what are your two biggest challenges?

Of four agents alpha, beta, gamma anddelta, three have to be sent together on amission. if alpha and beta cannot gotogether, beta and gamma cannot go togetherand gamma and delta cannot go together, then which of the following holds? 1. any three agents can be sent.2. alpha, delta and any one out of beta andv gamma can be sent.3. beta, gamma and any one out of alphaand delta can be sent.4. the mission is impossible.

What must students do with the 10 gird-ins on the math section of the psat

How many liters of 60% alcohol solution should be added to 40 liters of a 20% alcohol solution to make a 50% solution?