Rohan plants trees in a park. He plants 5 trees in the first hour, 8 in the second, 11 in the third and so on. Working at this increasing rate, in which hour does he plant the 100th tree (the hour in which the cumulative total first reaches or passes 100)?

Question

Accepted Answer

8th hour. Cumulative Sn = n/2[2(5)+(n-1)3] = n/2(7+3n). S7 = 7/2(28)=98, S8 = 8/2(31)=124. The total reaches 100 during the 8th hour.

Rohan plants trees in a park. He plants 5 trees in the first hour, 8 in the second, 11 in the third and so on.
Working at this increasing rate, in which hour does he plant the 100th tree (the hour in which the cumulative total first reaches or passes 100)?

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More Class 10 AP Word Problems practice

Rohan plants trees in a park. He plants 5 trees in the first hour, 8 in the second, 11 in the third and so on.Working at this increasing rate, in which hour does he plant the 100th tree (the hour in which the cumulative total first reaches or passes 100)?

Step-by-Step Solution

Master this chapter in 30 minutes a day.

More Class 10 AP Word Problems practice

Rohan plants trees in a park. He plants 5 trees in the first hour, 8 in the second, 11 in the third and so on.
Working at this increasing rate, in which hour does he plant the 100th tree (the hour in which the cumulative total first reaches or passes 100)?