Question

The A.P. in which 4th term is –15 and 9th term is –30. Find the sum of the first 10 numbers.​

Answer 1

Answer:

Step-by-step explanation:

Here is your answer mate....

Answer 2

Answer:

Hello ,

a+3d = -15 ---------(1)

a+8d= -30  (-)

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   -5d = 15

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d= -3

put d= -3 in equation (1)

a- 9 = -15

a = -6

sn = n/2 (2a+(n-1)d)

s10 = 10/ 2 (2 x -6 + 9(-3))

     = 5( -12 -27)

     = 5( -39)

     = -195

Good luck