a person has rs 210 .He wants to donate daily .If he donates rs 1 on first day ,rs 2 on second day and so on .how many days can he donates (ans is not 210)
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0
he donates money for
from 1 to 10th day he donated 55 rs
from 11th to 20 th day he will haven donated 210 rs
explanation
on 1st day 1 2nd 2 and so on
1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20=210
from 1 to 10th day he donated 55 rs
from 11th to 20 th day he will haven donated 210 rs
explanation
on 1st day 1 2nd 2 and so on
1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20=210
ankitkumar0102:
This can be easily solved using A.P
we have, a = 1, d = 1, Sn = 210. Put these value in formula Sn = n/2[2a + (n-1)d], where n is no. of day.
Answered by
1
money=210
sn=210
it is in ap form
f=1
d=1
sn=[tex] \frac{n}{2} [2f+(n-1)d] \\ 210*2=n[2+n-1)] \\ 420=n(1+n) \\ n ^{2}+n=420 \\ n ^{2} +n+0.25=420.25 \\ (n+0.5) ^{2} =420.25 n+0.5=20.5 n=20[/tex]
he donates in 20 days
sn=210
it is in ap form
f=1
d=1
sn=[tex] \frac{n}{2} [2f+(n-1)d] \\ 210*2=n[2+n-1)] \\ 420=n(1+n) \\ n ^{2}+n=420 \\ n ^{2} +n+0.25=420.25 \\ (n+0.5) ^{2} =420.25 n+0.5=20.5 n=20[/tex]
he donates in 20 days
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