Answer:
see attached
Step-by-step explanation:
Each spot in the triangle is the sum of the two numbers immediately above. The middle number of row 2 will be 1+1 = 2. The two numbers in row 3 will be 1+2 = 3 and 2+1 = 3. It continues like this. The second number in each row is the row number. Each row is symmetrical about the center.
This is exponential decay which can be expressed as:
y=ab^t, y=final value, a=initial value, b=rate, t=time
In this case a=25000, r=(100-20)/100=0.8 so
y=25000(0.8^t), so in 4.5 years...
y=25000(0.8^4.5)
y≈$9158.93 (to nearest cent)