find the sum of all two digit odd multiples of 3
brunoconti:
both solutions are wrong. resend for a solution
Answers
Answered by
2
first term (a) = 15
second term = 21
third term = 27
common difference (d) =21-15 = 6
last term(t)= 99
sum = [n(a+t)]÷2
n= (t-a)÷d
= (99-15)÷6 =14
sum=[14(99+15)]÷2
= 7×114 = 798
Answered by
3
ap is 15,21........99
a=15
d=21-15=6
an=99
a+(n-1)d=99
15+(n-1)6=99
(n-1)6=84
n-1=14
n=15
sn=n÷2 (a+an)
=15÷2(15+99)
=15÷2×114
=15×57
=855 is the sum
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