His average speed is 634/13 = 48,77 miles/hour. Well, he's fast :D
To find this out, use a percent proportion, use cross products, and solve the equation.

So, the percent tip is 14%.
Solution:
1. Move all terms to one side
<span>25{x}^{2}+40x+16-28=0</span>
2. Simplify <span>25{x}^{2}+40x+16-28 to <span>25<span>x<span><span>2</span><span></span></span></span>+40x</span></span><span><span>−12</span></span>
<span>25{x}^{2}+40x-12=0</span>
3. Apply the Quadratic Formula<span>x=\frac{-40+20\sqrt{7}}{50},\frac{-40-20\sqrt{7}}{50}
</span>
4. Simplify solutions
<span>x=-\frac{2(2-\sqrt{7})}{5},-\frac{2(2+\sqrt{7})}{5}</span>
Done!
40°, 60° and 80°
sum the parts of the ratio 2 + 3 + 4 = 9
The sum of the angles in a triangle = 180°
Divide 180 by 9 to find one part of the ratio
= 20° ← 1 part of the ratio
2 parts = 2 × 20 = 40°
3 parts = 3 × 20 = 60°
4 parts = 4 × 20 = 80°
The angles in the triangle are 40°, 60° and 80°
Answer:
x = 11/2 = 5.5
Step-by-step explanation:
2x-6 = 5
2x = 11
x = 11/2 = 5.5