(I think I'm posting in the right place, but not completely sure)

Question 1

The water used in the orchard is stored in a tank.

Each afternoon, 10% of the volume of water in the tank is used.

Each evening, 2 000 litres of water is added to the tank.

This pattern continues each day.

The volume of water, Vn , in the tank on the morning of the nth day is modelled by the difference equation

Vn + 1 = rVn + d where V1 = 45 000 litres.

a. Find r and d.

r =0.9

d =2000

b. In the long term, how many litres of water will be in the tank each morning?

Write your answer correct to the nearest litre

Question 2

A healthy eating and gym program is designed to help football recruits build body weight over an extended period of time. Rob, a new recruit who initially weighs 73.4 kg, decides to follow the program.

In the ﬁrst week he gains 400 g in body weight.

In the second week he gains 380 g in body weight.

In the third week he gains 361 g in body weight.

If Rob continues to follow this program indeﬁnitely, and this pattern of weight gain remains the same, his eventual body weight will be closest to

A. 74.5 kg

B. 77.1 kg

C. 77.3 kg

D. 80.0 kg

E. 81.4 kg

I tried S(infinity)=a/(1-r) But it can up with some crazy answer which couldn't be right.

Any help would be greatly appriciated.