Two spies have to communicate using a secret code. they need to create exactly 30 possible precoded messages, using a single number and letter. which structure should the code have?

a.
select a number from {1, 2, 3, 4} and a vowel.

b.
select a number from {1, 2, 3, 4, 5} and a vowel.

c.
select a number from {1, 2, 3, 4, 5, 6} and a vowel.

d.
select a number from {1, 2, 3, 4, 5} and a consonant.

Ineed to know the answer to this algebra question.

Match the vocabulary to the proper definition. in probability, two events in which 1. conditional probability the outcome of one event is independent of the outcome of a second event. 2. dependent events in probability, two events in which the outcome of one event is dependent on the outcome of a second event. the probability of an event in which the outcome of the event is conditional on the outcome of one or more different events. 3. independent events

Solve the system of equations using the substitution method. {y=−3x+7x=−2y−16 enter your answers in the boxes.