Answer:
of 1 a.
Jitendra made the savings in arithmetic sequence because saving is increased by 500 every month, means it's common difference is 500.
answer of 1. b.
soln
mean saving of Jitendra=(2000+3000)/2
= 2500
mean saving of Yankee=(400+1600)/2
= 1000
answer of 1.c
soln
n=5
a=2000
d=2500-2000
d=500
total saving of Jitendra= n/2[2a+(n-1)d]
=5/2[2×2000+(5-1)500]
=5/2[6000]
=15000
r=800/400
r=2
a= 400
n=5
total saving of Yankee=a(1-r^n)(1-r)
=400(1-2^5)(1-5)
=400×(1-32)×(-4)
=400×(-31)×(-4)
=12400