SOLUTION: If a boy saved P25 on the firat day, P27 on the second day, P29 on the third day and so on, how many days will it take to save P880?

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Question 940714: If a boy saved P25 on the firat day, P27 on the second day, P29 on the third day and so on, how many days will it take to save P880?
Answer by krutarthas(22) About Me  (Show Source):
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If a boy saved P25 on the firat day, P27 on the second day, P29 on the third day and so on, how many days will it take to save P880?
letus take n days
P880 = P25 + P27 + P29 + .....
AS WE KNOW THIS IS AN ARITHMATIC PROGRESSION
Sn=n(2a1+(n-1)d)/2
HERE Sn=880, a1=25 d=2
⇒880=n(2x25+(n-1)2)/2
⇒880=25n-nē-n
⇒nē-24n-880=0
⇒nē-44n+20n-880=0
⇒n(n-44)+20(n-44)=0
⇒(n-44)(n+20)=0
⇒n=44 or,n= -20 which is impossible
⇒n=44
in 44 days it will take to save P880
answer
Krutartha