Question

A man saves Rs 320 during the first month, as 360
in the second month, Rs. 400 in this third month.if he
continues his saving in this sequence, in how many month
will he saves RS, 20000?​

Answer 1

Answer:

Step-by-step explanation:

A.P. = 320, 360, 400...

a = 320

d = 360 - 320 = 40

Sn = 20000

Formula =>

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

20000 = n/2(2×320 + (n - 1)40)

20000 = n(320 + (n - 1)20)

20000 = n(320 + 20n - 20)

20000 = 300n + 20n²

20n² + 300n - 20000 = 0

20(n² + 15n - 1000) = 0

n² + 15n - 1000 = 0

n² + 40n - 25n - 1000 = 0

n(n + 40) - 25(n + 40) = 0

(n + 40)(n - 25) = 0

n = -40 or 25

Months can't be negative so it should be positive.

Therefore in 25 months it will save ₹20000

Hope it helps!

Please mark brainliest

Answer 2

Answer:

500 is the supposed answer plz tell it is correct or not.