Well, we could try adding up odd numbers, and look to see when we reach 400. But I'm hoping to find an easier way.
First of all ... I'm not sure this will help, but let's stop and notice it anyway ...
An odd number of odd numbers (like 1, 3, 5) add up to an odd number, but
an even number of odd numbers (like 1,3,5,7) add up to an even number.
So if the sum is going to be exactly 400, then there will have to be an even
number of items in the set.
Now, let's put down an even number of odd numbers to work with,and see
what we can notice about them:
1, 3, 5, 7, 9, 11, 13, 15 .
Number of items in the set . . . 8
Sum of all the items in the set . . . 64
Hmmm. That's interesting. 64 happens to be the square of 8 .
Do you think that might be all there is to it ?
Let's check it out:
Even-numbered lists of odd numbers:
1, 3 Items = 2, Sum = 4
1, 3, 5, 7 Items = 4, Sum = 16
1, 3, 5, 7, 9, 11 Items = 6, Sum = 36
1, 3, 5, 7, 9, 11, 13, 15 . . Items = 8, Sum = 64 .
Amazing ! The sum is always the square of the number of items in the set !
For a sum of 400 ... which just happens to be the square of 20,
we just need the <em><u>first 20 consecutive odd numbers</u></em>.
I slogged through it on my calculator, and it's true.
I never knew this before. It seems to be something valuable
to keep in my tool-box (and cherish always).
Y=2x+1... I hope this helps love! :)
Answer:
4/3 or 1 1/3
Step-by-step explanation:
Answer:
5
Step-by-step explanation:
Answer:
Month 1 : 0.002988
Month 2: 0.00299692814
Month 3: 0.00300588297
Step-by-step explanation:
Since we're only finding the interest for the first three months, it's easy to do it by performing the simple interest formula. But first, we need divide 3 by 12, since we calculate interest using years. 3/12 = 1/4 = 0.25
The standard simple interest calculation is done by multiplying the starting amount, by the interest, by the time, then dividing by 100 to put it into a percentage.
1 month = 1/12 or approximately 0.083 of the year.
Let's say P = 1. For the first month, it will be 1 x 3.6 x 0.083 = 0.2988 / 100
The second month, (1 + 0.002988) * 3.6 * 0.083 = 0.299692814 / 100
The third month, (1.002988 + 0.00299692814) x 3.6 x 0.083 = 0.300588297/100
Given the initial amount be 1, those would be the periodic interest rate during the first three months.
