Shaahikala needs Rs.7000 after 15 weeks to send her daughter to school. She saved Rs.150 in the 1st week and raises by Rs.50 every succeeding week. Find whether she will be able to send her to school after 15 weeks? What value is created by the above situation in you?

Pls answer asap!!...🙏🏻

So you are looking at an arithmetic series :

150 + 200 + 250 + .... ≥ 7000
We need to find the number of terms for this to be true.
let the number of terms be n
a = 150, d = 50, n = ?, sum(n) = 7000

(n/2)(2a + (n-1)d) = 7000
(n/2)(300 + 50(n-1)) = 7000
n(300 + 50n - 50) = 14000
50n^2 + 250n - 14000 = 0
n^2 + 5n - 280=0
n = appr 14.4 or a negative

so she will need her 15th payment to get to 7000, so yes, she has enough money in the 15 weeks

check:
sum(14) = 7(300 + 50(13)) = 6650 , not enough
sum(15) = (15/2)(300 + 50(14)) = 7500