Answer:
After 460 calls plan 1 is more economical than plan 2
Step-by-step explanation:
Plan 1: 36x + 0y
Plan 2: 13x + 0.05y
36x < 13x + 0.05y
36x - 13x < 0.05y
23x < 0.05y
23/0.05x < y
460x < y
Answer:
Umm... I don't know.... Sorry.....
Step-by-step explanation:
a e I o u y are all vowels if that helps
5.
Let x be the age of the father and y be the age of the son. As of today, he's 3 times older, so we have 
10 years ago their ages were, respectively, x-10 and y-10, and the father was 5 times older: 
So, we have the system

Using the first equation, we can substitute every occurrence of "x" with "3y" in the second equation:

So, the son is 20 years old, which means that the father is 60 years old.
Indeed, 10 years ago they were 10 and 50 years old, so the father was 5 times older.
6.
Let x be the age of the grandfather and y the age of the granddaughter. We know that the grandfather is 10 times older: 
He also is 54 years older: 
Again, if we substitute x=10y in the second equation we have

Answer:
B
Step-by-step explanation:
V=
V=3.14*
*3
V=3.14*
*3
V=3.14* 64*3
V=602.88 which rounds up to 602.9