6. At a medical convention, there are 7 pediatricians, 5 cardiologists, 3 nurses and 4 dermatologists. If a participant is selected at random, what is the probability
of selecting a pediatrician or a cardiologist?

Adice is rolled 5 times. how many possible rolls are there? ( determine the number of outcomes using only the fundamental counting principal )

The u-drive rent-a-truck company plans to spend $13 million on 320 new vehicles. each commercial van will cost $25 comma 000, each small truck $50 comma 000, and each large truck  $80 comma 000. past experience shows that they need twice as many vans as small trucks. how many of each type of vehicle can they buy?

Si la base de un triángulo isósceles mide 70 m y el ángulo opuesto a ésta mide 58°; entonces ¿cuánto mide la altura de dicho triángulo? a) 21.87 m. b) 40.01 m. c) 43.74 m. d) 63.14 m.