Thomas had 19 problems correct of the 25 problems on a recent math quiz. What percent of the problems on the quiz did he answer correctly?
A.
24%

B. 36%

C. 76%

D.95%

76%

Step-by-step explanation:

Thomas got 19/25 marks.

** Note: Percents are always out of 100.

We don't know how many marks he got out of 100.

=> 19/25 = x/100

There are two ways to solve it from now.

=> Multiply 19 and 100; 25 and x

=> 25x = 1900

Next, Divide 25 on each side.

=> 25x/25 = 1900/25

=> x = 76

He got 76% on the quiz.

Another way is:

=> 19/25 = x/100

=> We need to divide 25 from 100.

=> We get 4.

So, 25 x 4 = 100

=> 19 x 4 = x

=> x = 76

He got 76% on the quiz.

Both ways are correct.

x is variable or an unknown value to find

example:

2x = 5 which means x = 3

a) one student is chosen from classroom a, then a student is chosen from classroom b.  

step-by-step explanation:

independent events are ones in which the probability of one event does not affect the probability of the second event.

one student is chosen from classroom a; this does not affect the chances of choosing a student from classroom b.   this makes these independent events.

when one card is chosen from a standard deck and then set aside before a second card is chosen, the probability of the second card being chosen changes.   this makes them dependent events.

when one student is chosen from classroom a and then a second student is chosen from classroom a, the probability of choosing the second student changes.   this makes them dependent events.

when a letter is chosen from the alphabet and then a second letter is chosen, the probability of choosing the second letter changes.   this makes them dependent events.