Yasmeen saves Rs 32 during the first month, Rs 36 in the second month, and Rs 40 in the third month. If she continues to save in this manner, in how many months will she save Rs 2000?

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answer is C.

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Detailed Solution

Given, Yasmeen saves Rs 32 during the first month, Rs 36 in the second month, and Rs 40 in the third month.
According to the question,
A = 32,
d = 36 - 22
= 4 and
Sn = 2000.
Substituting the above values, we get,

2000 = n 2 232 + n − 1 4 2000 = n 2 64 + 4 n − 1 2000 = 32 n + 2 n n − 1 n 2 + 15 n − 1000 = 0

Solving the quadratic equation

n 2 + 15 n − 1000 = 0

n 2 + 40 n − 25 n − 1000 = 0 n n + 40 − 25 n + 40 = 0 n = 25

And, n = -40 is ignored as the number of months cannot be negative.
So, 25 months more will be needed to save Rs.2000.
Therefore, the correct option is 3.

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