find the sum of all two digit odd multiples of 3
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3
two digit odd multiples of 3 are 15,21,......99
the following are in A.P with first term 15 and common difference 6 and nth term 99
99= 15+(n-1)6
84=(n-1)6
n=15
Sum of all the of multiples of 3
Sn=(15/2)(30+(14×6))
Sn=855
Answered by
2
Hey mate here is ur answer ---
15,21,27.........99
a=15
d=6
l=99
l=a+(n-1)d
99=15+(n-1)6
99-15=(n-1)6
84=(n-1)6
84/6=n-1
14=n-1
n=15...No of terms✓✓✓✓✓✓✓
Sn=n/2(a+l)
15/2(15+99)
15/2*114
15*57
855.Ans (sum )✓✓✓
Hope it's helps to u!!
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