<u><em>Answer:</em></u>
The slope of the line is 77
<u><em>Explanation:</em></u>
We know the speed is constant and that the mile-marker location over time can be represented by a line. This means that the equation is linear.
<u>The slope can, therefore, be calculated as follows:</u>

where (x₁ , y₁) and (x₂ , y₂) are two points on the line
We are given that the two points (1, 123) and (3, 277) are two points in the line
<u>Substitute with them in the above equation to get the slope as follows:</u>

Hope this helps :)
<span>Let x be the brother's weight.
Then 2x-5 is Andy's weight.
x+(2x-5)=100
3x-5=100
3x=105</span>
I did the test and the answer is 7.4 cm
good luck
hope it help!!!^_^