First term (a1) is -1
recursive formula goes like this

is the nth term

is the term before that
we normally have

we see each term is multipying by -3 to get next one
so that would be

where a1=-1
the 3rd option is correct except that it is the explicit formula
so answer is 2nd one
Answer:12
for every 2 boys that is 3 girls
there are 4 sets of two boys so you would have 4 sets of 3 girls
4×3=12
I hope this is good enough:
20/45 would be 4/9 in simplest form. hope that helped
60x0.25=15
60x0.10=6
51x0.25=12.75
13.35-12.75
D-6
Q-51