A school distributes notebooks in an AP over several days. On day 1 it gives 25 notebooks and 2 fewer each following day. The total given out is 144 notebooks. Find the number of days (take the smaller valid value).

Question

Accepted Answer

8. a = 25, d = -2. Sn = n/2[50+(n-1)(-2)] = n/2(52-2n) = n(26-n) = 144, so 26n - n^2 = 144, n^2 - 26n + 144 = 0. Factor: (n-8)(n-18) = 0, n = 8 or 18. Beyond n=13 terms turn negative, so the valid smaller value is n = 8.

A school distributes notebooks in an AP over several days.
On day 1 it gives 25 notebooks and 2 fewer each following day.
The total given out is 144 notebooks.
Find the number of days (take the smaller valid value).

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More Class 10 AP Word Problems practice

A school distributes notebooks in an AP over several days.On day 1 it gives 25 notebooks and 2 fewer each following day.The total given out is 144 notebooks.Find the number of days (take the smaller valid value).

Step-by-Step Solution

Master this chapter in 30 minutes a day.

More Class 10 AP Word Problems practice

A school distributes notebooks in an AP over several days.
On day 1 it gives 25 notebooks and 2 fewer each following day.
The total given out is 144 notebooks.
Find the number of days (take the smaller valid value).