Let the value of first certificate = Rs x
each year, it the value is increased by 100. So the prices of the certificate forms an A.P. with common difference 100
So first term,a=x, common difference,d = 100
In 10 years, he will have 10 cards.
a. Value of first certificate = Rs. 5000
b. For eighth year, n=8
value = 5000+(8-1)100 = Rs. 5700