Answer:
A. On the first day, 3 leaves fall.
B. D. The number of leaves that fall on a given day is 2 times the number of leaves that fell on the previous day.
Step-by-step explanation:
Given

Solving (a) The meaning of 3.
3 represents the initial number of leaves (i.e. the first day) and this proved as follows.
On the first day, n = 0.
Substitute 0 for n in 



Solving (b) The meaning of 2.
2 represents the rate which leaves fall down.
In (a)

Take n = 1
Substitute 1 for n in 



When f(1) is divided by f(0), the result 2. So, the number of leaves doubles everyday
Answer:
a4 = 128
a5 = -512
Step-by-step explanation:
a1= -2
q= (-1)^(n+1) × 4
a4 = a1q³ = (-2) (-4)³ = -2 × -64 = +128
a5 = a1q⁴ = (-2) (-4)⁴ = -2 × 256 = -512
<u>Answer:</u>
A = 70
B = 90
<u>Step-by-step explanation:</u>
We know that Car A travels 20 mph faster than Car B.
Assuming the speed of Car B to be x and the speed of Car A to be x+20, we can write:

Taking the reciprocal of both sides to make x the subject:




---> speed of Car A
Finding the speed of Car B: 
Therefore, the speed of Car A = 70 and the speed of Car B = 90.