Step 1
Given;

Required; To find the difference in interest between the two periods.
Step 2
State the formula for simple interest

Step 3
Find the interest when the rate is 8%

Therefore the interest is given as;

Step 4
Find the interest in 1980 with a 20% rate

The interest is given as;

Step 5
Find the difference in interest between the two rates.

Hence, the difference in interest between the two rates = $11095.89
Answer:
CACULATOR: shift solve= ---> x= π
Step-by-step explanation:
Find the slop equation.
Slope: -3
Y-intetrcept: -3

Now write it as an inuquality.
It's shaded to the left and the line is not fully filled in. Which means that whatever "y" is, it's Less than the and equal to the slope.

Hope this helps :)