Because, that's just how math works.
Answer:
1a. 42% of teens spend time playing games on their phones
2a. Collecting data would be difficult because you have t figure out what state in the U.S to use.
3a. 513 students from 84 colleges nationwide found that 34.89 percent of them spend a lot of time playing games on their smartphones, and 42.69 percent play occasionally.
Answer: 43 and 49
Step-by-step explanation:
1st:x
2nd x+2
3rd: x+4
(x)+(x+2) = 3(x+4)-31
distribute
2x+2 = 3x+12-31
2x+2 =3x-19
subtract 2x from each side
2 = x-19
add 19 to each side
21 =x
Answer: 21,23,25
