Friday 27 June 2014

ARITHMETIC PROGRESSION-1


Find the sum of the 1st 16 terms of the following arithmetic progression: 5+11+17+…………………

Solution

d=6, A1 = 5,n=16

Sn = n[2A1 + (n-1)d]
       2

S16 = 16[2(5) + (16-1)d]
         2

S16 = 8[10 + 15d]
 
S16 = 8[10 + 15(6)]       since d=6

S16 = 8[10 + 90]
           
S16 = 8 x 100  
         
S16 = 800


Therefore the sum of 1st 16 terms is 800.


TRY THIS......


Find the sum of the 1st 16 terms of the following arithmetic progression: 6+14+22+…………………

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