Question

find x: 20+19+18.......x = 200​

Answer 1

Answer:

can you repeat the question again

Step-by-step explanation:

Answer 2

Step-by-step explanation:

a = 20

d = -1

S = 200

S = n{2a + d(n-1)}/2

200 = n { 40 - 1(n - 1)} /2

400 = 40n - n² + n

n² - 41n + 400 = 0

n² - 16n - 25n + 400 =0

n (n - 16) - 25 (n - 16) = 0

(n - 25)(n - 16) = 0

(n - 25) = 0 (or) (n - 16) = 0

n = 25 (or) n = 16

x = a + (n - 1)d

x = 20 - (n - 1)

x = 21 - n

x = 21 - 25 (or) x = 21 - 16

x = -4 (or) x = 5

x cant be negative

so, x = 5

Hope this helps!

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