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:
Step-by-step explanation:
2( N+ 17) = 3 (N +7)
2N+ 34= ·3N+ 21
N= 13
D= N+8 = 13+8 = 21
Fraction is 
When Im using N is equal to numerator and D for denominator, in order to get the fraction we substitute and the results combine in the fraction like this 
Answer:
the measure of AB =29 meters