Question

Each year a tree grows 5 cm less than it did the preceding year. If it grew by 1m in the first year in how many year will it have creased growing?

Answer 1

Given: The tree grow 1 m = 100 cm in first year and grow 5 cm less in the preceding years

 clearly the growth of  the tree in years i.e.

100, (100 – 5), (100 – 2 × 5)

= 100, 95, 90 ...

forms an A. P. with first term (a) = 100 and common difference (d) = –5

 

Let in n years the tree will ceased growing



 

Hence the tree will have ceased growing in 21 years

Answer 2

after 21 years..... ...