an ap 5,12,19....has 50terms .find its last term .hence find the sum of its last 15 tems
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Step-by-step explanation:
AP=5,12,19.........
a=5
d=12-5
=7
n=50
l =a+(n-1)d
l =5+(50-1)7
l =5+(49)7
l =5+343
l =348
last term =348
S15 =n/2 (a +l)
S15= 50/2(5+348)
S15=25(353)
S15= 8825.
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