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avatar+9479 
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1.

 

Remember:       distance   =   rate * time

 

Since he was going at two different rates for each part of the trip, lets first calculate the distance he flew during the first part of the trip and then we can calculate the distance he flew during the second part of the trip. The total distance traveled will be the sum of these two distances.

 

distance1   =   rate1 * time1   =   680 mi/hr  *  (3.8 / 2) hr   =   680 mi/hr   *   1.9 hr   =   1292 mi

 

distance2   =   rate2 * time2   =   740 mi/hr  *  (3.8 / 2) hr   =   740 mi/hr   *   1.9 hr   =   1406 mi

 

total distance   =   distance1  +  distance2   =   1292 mi  +  1406 mi   =   ?

 

 

 

2.

 

By solving the first formula for time,  we get:       time   =   distance / rate

 

Again let's split this into two parts for each part of the trip.

 

For the 1st part..... the distance is one third of the total distance, and the rate is 1032 km/hr.

For the 2nd part.... the distance is two thirds of the total distance, and the rate is 696 km/hr.

 

\(\text{time}_1\ =\ \dfrac{\text{distance}_1}{\text{rate}_1}\ =\ \dfrac{\frac13\cdot1860\ \text{km}}{1032\ \frac{\text{km}}{\text{hr}} } \ =\ \dfrac{620\ \text{km}}{1032\ \frac{\text{km}}{\text{hr}} }\ =\ \dfrac{620}{1032}\ \text{hr}\)

 

\(\text{time}_2\ =\ \dfrac{\text{distance}_2}{\text{rate}_2}\ =\ \dfrac{\frac23\cdot1860\ \text{km}}{696\ \frac{\text{km}}{\text{hr}} }\ =\ \dfrac{1240\ \text{km}}{696\ \frac{\text{km}}{\text{hr}} }\ =\ \dfrac{1240}{696}\ \text{hr}\)

 

\(\text{total time}\ =\ \text{time}_1+\text{time}_2 \ =\ \dfrac{620}{1032}\ \text{hr}\ +\ \dfrac{1240}{696}\ \text{hr}\ =\ \Big( \dfrac{620}{1032}\ +\ \dfrac{1240}{696}\Big)\ \text{hr}\ \approx\ 2.38\ \text{hr} \) _

Sep 16, 2020
 #1
avatar+9479 
0

Since vertical angles are congruent, we can make the following equation:

 

(4x + 7)°   =   (7x - 35)°

                                           We can remove the degree signs and parenthesees from both sides of the equation.

4x + 7   =   7x - 35

                                           Subtract 4x from both sides, add  35  to both sides.

7 + 35   =   7x - 4x

                                           Combine like terms.

42   =   3x

                                           Divide both sides of the equation by  3

?   =   x

 

 

 

 

Alternate approach:

 

Since a  180°  angle forms a straight line, we can make the following equation:

 

(4x + 7)°  +  (10x - 23)°   =   180°

                                                       Remove the degree signs from every term, then we can drop the two

                                                       sets of parenthesees because there is only addition between them

4x + 7  +  10x - 23   =   180

                                                       Simplify the left side by combining like terms.

14x  -  16   =   180

                                                       Add  16  to both sides.

14x   =   196

                                                       Divide both sides of the equation by  14

x   =   ?

Sep 16, 2020
 #1
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Sep 16, 2020

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