` a=3 ,n =8 ` और ` S= 192` दिया है|d ज्ञात कीजिए| एक `A.P.` में,

Explanation

` a=3 ,n =8` तथा ` s = 192`
`" " S= 192 `
` rArr " " (n)/(2) [2a +(n-1)d] =192`
` rArr " " (8)/(2) [2xx 3 +(8-1) d] =192` ltbr gt ` rArr " " 4(6+ 7d ) =192`
` rArr " " 24 + 28d =192` ltbr gt ` rArr " " 28 d= 192 -24 =1681`
` rArr " " d=(168)/(28) = 6`
` therefore " " d=6`