Student of standard X to plant 300 trees in a rows, to form an isosceles triangle. The number of trees in the successive rows increasing by one from the starts by 1 tree to the base. How many trees the student have to plant in the row which forms the base of the triangle ?

Answer 1

If I understand your question ....
1+2+3+4+...+n = 300
you have an AS with a=1, d=1

sum(n) = (n/2)(2a + (n-1)d) = 300
n(2 + n-1) = 600
n^2 + n - 600 = 0
(n+25)(n-24) = 0
n = 24, since n > 0

term(24) = a + 23d = 1 + 23 = 24

Answer 2

Bad

Answer 3

Thanks

Answer 4

Very nice