 Hello and welcome to this session. Let us understand the following problem today. In an AP given A is equal to 8, An is equal to 62, Sn is equal to 210, find N and D. Now let us write the solution. We know An is equal to A plus N minus 1 D. Now in order to find the value of D substituting, the values we get, An is equal to 62 which is equal to A is equal to 8 plus N minus 1 D which implies 62 minus 8 is equal to N minus 1 multiplied by D which implies 54 is equal to N minus 1 D which implies D is equal to 54 divided by N minus 1. Now we know Sn is equal to N by 2 multiplied by 2A plus N minus 1 D. Now substituting the values Sn given to us is 210 which is equal to N by 2 multiplied by 2 multiplied by 8 plus N minus 1 multiplied by D which is equal to 54 divided by N minus 1. Now here we see that this and this gets cancelled. So we get it implies we take 2 on this side so we get 420 is equal to N multiplied by 16 plus 54 which implies 420 is equal to N multiplied by 70. Now which implies N is equal to 420 by 70. Now this gets cancelled by 2 so we get here 210 and similarly here we get 35. Now we cancel it by 5 so we get here 4, 2 and here 7. Now we cancel it by 7. 7 is equal to 42 so which implies N is equal to 6. Now substituting N is equal to 6 and D is equal to 54 divided by N minus 1 which implies D is equal to 54 divided by 6 minus 1 which implies D is equal to 54 divided by 5. Hence N is equal to 6 and D is equal to 54 divided by 5 is our required answer. I hope you understood the question by and have a nice day.