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The Brainliest Answer!
2014-08-31T19:05:13+05:30
First term a = 2
let common difference = d
Tn = a + (n-1)d
47 = 2 + (10-1)d
d = 5
Sn = n[2a + (n-1)d]/2
S15 = 15[2*2 + 14*5]/2
S15 = 15*37 = 555
 
2 5 2
vikas - there is an equation editor, in the answer window. you see a button marked with symbol Pi. click on it. The solution looks better. thanks.
2014-08-31T21:52:02+05:30

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T_{10} = 47 = 2 + (10-1) d \\ \\ 47 = 2+9d \\ \\ d = 5 \\ \\ S_{n}  = a*n+\frac{d*n(n-1)}{2} \\ \\ S_{15} = 2*15+\frac{5*15*14}{2} = 30+525 = 555 \\
1 5 1