The answer for 19 is a & d
The answer for 20 is 8607
The answer for 21 is 85.10
Even though I am a senior in high school I know the answer
The a is 11
g(4)=20+a
g(4)=31
31-20=11
a=11
Answer:
There are 32 pupils in the class
Step-by-step explanation:
Let's say there are N pupils in the class. Then each pupil must send N-1 cards - because it would make no sense to send one to themselves! So each of the N pupils send N-1 cards, which becomes 992 cards in total. In equation form, this is
This is a second degree polynomial, which has the solutions
where
If we insert these numbers in the equation,
If we choose the solution with the minus sign, we get
N=-31
but this makes no sense! There can't be a negative number of pupils in the class!
So we choose the solution with the plus sign,
So there are 32 pupils in the class
I think it's letter A because if u just look at it you can tell that by dividing each number you'll get your answer