Answer:
309 full rolls
Step-by-step explanation:
Find how many full rolls he had by dividing 15,483 by 50:
15,483/50
= 309.66
Since the question asks for full rolls, the answer has to be a full number.
So, the answer is 309 full rolls
15·0.8 + x = 30·0.9 --> x = 15
C. is the correct answer
C because it's on the next one
The two equations are

and

the first equation can be solved for x to be

next you can substitute x in the second equation

Distribute 4 to everything in the parentheses

combine like terms:

subtract 28 from both sides of the equation

divide both sides by -1.5

plug this in to the original equation of x+y=7

subtract 4 from both sides.

Final Answer: they bought 3 adult tickets and 4 student tickets
Hope this helps!
The of the first multiples of 21 is 21, 42, 63, 84, 105