Simultaneous Equations
2u + b = $110
4u + 3b = $268
(x2) 4u + 2b = $220
(x1) 4u + 3b = $268
<em />If both the matching coefficients are the same, we subtract equation 2 from equation 1
2b - 3b = -b
$220 - $268 = $-48
-b = -$48
b = $48
If you want to find out what a unicycle costs...
Substitute b = $48 into the first equation
2u + $48 = $110
Balance the equation, whatever happens on one side, happens on the other.
2u + $48 (-$48) = $110 (-$48)
2u = $62
2u(/2) = $62(/2)
u = $31
The correct answer is this one: "C. 5+5=10 "
From the equation 6 + 5 = 11
We can have the doubles : 5 + 5 + 1 = 11
<span>The doubles plus one are the facts in which one addend is larger than the other by one.</span>
Here are the choices.
A- 8+8=16 B- 7+7=14
C- 5+5=10 D- 4+4=8
Margin error of a sample mean is given by

where σ is the standard deviation,

is the critical value and n is the sample mean.
So beside the given standard deviation, we're supposed to know the sample size and critical value to answer this question.