ICSE Class 10 Maths Word Problems of A.P.

please tell the final answer
 What is AP

3(b)
 determine which term of the AP 121,117,113 ....... is the first negative term

Ap gp
 Divide 96 into four parts which are in AP and the ratio between product of their mean to product of their exterme is 15:7
 If the sum of first m terms is n,and sum of first n terms is m,show that sum of first (m+n) terms is equal to (m+n)
 Kanika was given her pocket money on 1st Jan 2016 .she puts ₹1 on day 1,₹ 2on day 2 and ₹ 3 on day 3 and continued on doing so till the end of the month ,from this money into her piggy bank. She also spent ₹204 of her pocket money and was found that at end of the month she still has ₹100 with her . How much money was her pocket money for the month?
 If 8times of the 8th term of an AP is equal to 13 times of the 13th term, show that 21st term of an AP is zero.
 The 3rd term of an GP is 4. Find the product of its first 5 terms.