Question

Five friends agree to save money for a graduation road trip. They decide that each of them will put $0.25 in the fund on the first day of May, $0.50 on the second day, $0.75 on the third day, and so on. At the end of May, there will be $_____ in their fund. (Hint: There are 31 days in May.)

Answer 1

$0.25 + $0.50 + $0.75 + ...
What type of sequence is this, arithmetice or geometric?

Answer 2

um i think arithmetice

Answer 3

Correct, since there is always a fixed difference (called "common difference") between any two consecutive terms

Answer 4

You know the first term of the series is 0.25.
The common difference is 0.25.
You need to find the sum up to term number 31.

Answer 5

The sum is Sn = n(a1 + an)/2
where n is the number of the last term. In this case, n = 31.
a1 is the first term, which in this case is 0.25.
a31 is the 31st term.
The formula for an is:
an = a1 + (n -1)d

Answer 6

After you find the sum, multiply it by 3 since there are three people contributing to the fund.

Answer 7

Are you following this?

Answer 8

23.25???

Answer 9

How did you get that?

Answer 10

You need three steps:
1. Find a31, the 31st term of the series
2. Find S31, the sum of the series up to and including the 31st term
3. Multiply S31 by 3

What did you get for a31?