Question

In an A.P consisting of 27 terms, the sum of the first three terms is 21 and
that of the three middle terms is 93. Find the first term and the common
difference.​

Answer 1

Answer:

yen Guillermo zydeco Buddho burlap Delgado burlap

Explanation:

studio surgical Voronezh Hornick

Answer 2

$\bf{ \underline{ \underline{ \overline { \overline{Given }}}}}$

• Total terms in AP = 27 terms

• Sum of 3 middle terms = 93

• Sum of 1st 3 terms = 21

$\bf{ \underline{ \underline{ \overline { \overline{To\ find }}}}}$

• Common difference.

$\bf{ \underline{ \underline{ \overline { \overline{Solution }}}}}$

• Let the 1st three terms as = a , a+d , a+ 2d

→ a + a + d + a + 2d = 21

→ 3a + 3d = 21

→ a + d = 21/3

→ a + d = 7 .

→ d = 7-a

• Middle terms of AP = 13h , 14th and 15th

→ a + 12d + a+13d + a+14 d = 93

→ 3a + 39d = 93

→ 3 a + 39(7-a) = 93

→ 3a + 273 - 39a = 93

→ 273 -93 = 36a

→ 180 = 36a

→ a = 5

→ d = 7-5

• d = 2 .

Common difference is 2