Problem Solving with Rational Numbers in Decimal Form
The mean of six rational numbers is -4.3
a) What is the sum of the rational numbers?
b) If five of the numbers each equal -4.5, what is the sixth number?
First of when looking at the question the first thing that pops into some people's minds is, what is a mean? A mean is a way of calculating the average of a set of numbers by adding all the numbers together and diving by the amount of numbers in the set.
For a) we would first think how the mean is -4.3.
We know that x/6 = -4.3
X is the sum of the rational numbers.
In order to find that sum I used reverse operations to isolate x.
x/6 X 6 = -4.3 X 6
x = -25.8
The sum of the rational numbers is -25.8.
For b) I like to write it down using algebra.
[(-4.5) + (-4.5) + (-4.5) + (-4.5) + (-4.5)] + x = -25.8
Here 5 out of the six numbers are -4.5 just like the question says.
When added the numbers are...
(-22.5) + x = -25.8
I like to isolate the x by using the reverse operation.
(-22.5) - (-22.5) + x = -25.8 - (-22.5)
x = -3.3
The sixth number is -3.3.
If you have any questions concerning this post or anything about chapter 2, feel free to ask me or if I don't know go see Mr. Backe in the morning.