Answer:
I = a/300
A = (300I + a)/300
Step-by-step explanation:
David earns 4% for the money he has in savings. Let the amount that he has initially be a. This means that his principal is a. So
P = a
The rate at which he is earning interest on the principal is 4%. Therefore,
R = 4℅
We want to calculate the amount of money in his account after one month. This means that time,
t = 1/12 (12months make a year)
The amount of money in his account after one month will be the interest earned in one month + the initial amount in the account.
To determine the interest, we will apply the simple interest formula,
I = PRT/100
Where I = interest
P = principal
T = time
The first equation will be
I = (a × 4 × 1)/12 × 100
I = 4a/1200 = a/300
The second equation will be
Amount in the account after one month,A
A = I + a/300
A = (300I + a)/300