Rjayzaballa19id
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1. To save for the class field trip, Celia deposited P75 into her savings account on the first week, P100 on the second week, P125 on the third week, and so on until she had enough money for the trip. If it took her 12 weeks to save the target amount, how much money did she save for the field trip? A. P2,500 B. P2,550 C. P2,250 D. P2,050. ​

1 To Save For The Class Field Trip Celia Deposited P75 Into Her Savings Account On The First Week P100 On The Second Week P125 On The Third Week And So On Until class=

Sagot :

Ncteologyid

We know this is an arithmetic sequence

So [tex] \tt a_{1} = 75, \: \: d = 25[/tex]

So [tex] \tt a_{n} = a_{1} + (n - 1)d[/tex]

[tex] = \tt75 + (n - 1) \times 25 [/tex]

[tex] \tt = 25n + 50[/tex]

So when [tex] \tt n = 12[/tex]

[tex] \tt a_{12} = 25 \times 12 + 50[/tex]

[tex] \tt\:\:\:\:\:\: = P350[/tex]

So [tex] \tt s_{12} = \frac{12 \times (75 + 350)}{2} [/tex]

[tex] = \tt6 \times (75 + 350)[/tex]

[tex] \tt = 2550[/tex]

[tex] \\ [/tex]

Answer: B