John was born in January. On the first July 4th of his life, his aunt gives him $50 to save for his college education. On every subsequent July 4th, she gives him $25 dollars more than the previous year. What will John's aunt give him on his 18th July 4th?
A. $475
B. $450
C. $425
D. $500
John was born in January. On the first July 4th of his life, his aunt gives him $50 to save for his college education.....?
2020-10-29 11:15 pm
回答 (3)
2020-10-29 11:25 pm
The sequence is arithmetic:
50, 75, 100, ...
You could just add terms until you get to 18 terms.
Or you could use the formula for the nth term of an arithmetic sequence.
a[n] = a + d(n - 1)
a : first term (50)
d : common ratio (25)
n : number of terms (18)
a[18] = 50 + 25(18 - 1)
a[18] = 50 + 25(17)
a[18] = 50 + 425
a[18] = 475
Answer:A. $475
50, 75, 100, ...
You could just add terms until you get to 18 terms.
Or you could use the formula for the nth term of an arithmetic sequence.
a[n] = a + d(n - 1)
a : first term (50)
d : common ratio (25)
n : number of terms (18)
a[18] = 50 + 25(18 - 1)
a[18] = 50 + 25(17)
a[18] = 50 + 425
a[18] = 475
Answer:A. $475
2020-10-29 11:19 pm
DO YOUR OWN HOMEWORK..
2020-11-01 12:32 pm
a_n = 25 (n + 1)
a18 = $475
A. $475
a18 = $475
A. $475
收錄日期: 2021-05-01 22:16:07
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