Question 1203622: Rowena saved 100 pesos on her daughter's first birthday. On her second birthday, she saved 300 pesos. On her third birthday, she saved 900 pesos and so on up to her daughter's 18th birthday. How much did Rowena saved for her daughter?
Answer by mananth(16946)   (Show Source):
You can put this solution on YOUR website! Rowena saved 100 pesos on her daughter's first birthday. On her second birthday, she saved 300 pesos. On her third birthday, she saved 900 pesos and so on up to her daughter's 18th birthday. How much did Rowena saved for her daughter?
Amount saved
Ist. Birthday ----------100 pesos
2nd. Birthday --------- 300 pesos
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3rd. Birthday ---------900 pesos
100,300,900,...............
Savings are in Geometric progression
300/100 = 3, 900/300 = 3
Total saved = ?
Sum of n terms of GP, Sn = a(1 - r^n) / (1 - r), when
a = 100 , r =3 n=18
19,371,024,400 pesos aved
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