Answer:
a > -2
Step-by-step explanation:
-12a +7<31
Subtract 7 from each side
-12a +7-7<31-7
-12a <24
Divide by -12, remembering to flip the inequality
-12a/-12 >24/-12
a > -2
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:
I believe it is 21
Step-by-step explanation: