ImDecentAtMath

This is pretty easy. All numbers with 3 as a factor terminate when divided by 3. So find the amount of numbers that are multiples of 3 in your range. 474 is the 158th multiple of 3, so 158 numbers.

I think you forgot 3 own both in step 3. It's 21 since you do 16+8=24 as you did but then subtract 3 to get 21 as the answer.

6 students take both languages. 43+48+n=97 and this simplifies to n=97-91 or n=6.

8/24=(1*8)/(3*8)=1/3 * 8/8=1/3

So 8/24 =1/3.

0,12-->0% win-->n=4

2,13-->13.3%win-->n=5

4,15-->21.05%win-->n=6

6,16-->27.27%win-->n=7

8,17-->32%win-->n=8

10,18-->35.7%win-->n=9

12/19-->38.71%win-->n=10

14/20-->41.18%win-->n=11

16/21-->43.24%win-->n=12

18/22-->45%win-->n=13

We can clearly see the win percentage goes above 40% after week 11. So n is 11.

Well, this question can be written with several equations. We can say m is the amount of money to write m>=200. We can also say 80+(3/4)(m-80)>m-200 which becomes 3m/4+20>m-200 or 20>m/4-200 or 220>m/4 or finally m<880. We can check this by checking whether 80+(3/4)(880-80)>(880)-200. If we simplify that, we get 680>680 which is not true since they are equal. Now we have set the upper limit. We can also check whether 200 dollars itself works. We can do 80+3/4(200-80)>(200)-200 which works. This means all the numbers from 200 up to 880, including 200 but not 880, work as possible value. 

The answer as an interval is [200,880).

I'm pretty sure this question is impossible. We can say t=800+x where t is your truck and x is her trucks and then write t<=(1/5)(4x) which is also t<=4x/5. Let's assume t=4x/5. Then if we solve the equation we get x=-4000 which is clearly not possible since the truck shouldn't carry a negative weight. Also, if t=4x/5 -1, we subtract 1 to put an equal sign instead of a < sign, then we get x=-4005 and x is decreasing in value(since it is negative) and so we can never get a positive answer. This means the problem shouldn't be possible. 

This I think should be simple. I hope I'm not getting too overconfident but I think it's just (3/6)*(2/5)*(1/4)=1/20.

So the chance of everyone getting a red card is 1/20.

It's in japanese. But I'm not sure exactly what they're saying. Something about a question about math I think.

Well, Ig you could just keep doing the function, but I am sure there is a more efficient way. If you just repeat the function you do f(f(f(17)))=f(f(3(17)-1))=f(f(50))=f(3(50)-1)=f(149)=3(149)-1=446.

So f(f(f(17)))=446.

Even if there's a more efficient way, no matter what, you should get 446 as your answer.