Let

be the amount of time it takes to perform an arm routine and

be the amount of time it takes to perform an abdominal routine. We see:


Subtracting the second equation from the first gives

. Substituting gives

, so

and

.
Thus, an arm routine takes ten minutes and an abdominal routine takes thirty minutes.
Step-by-step explanation:
Alrighty! here you go image.
Answer:
80 km/hr
Step-by-step explanation:
This is asking for speed.
Speed=Distance/Time
Speed=720/9
Speed=80 km/hr

According to given figure, The Triangle BDC is a right angled Triangle (Angle D = 90°)
So, we can apply Pythagoras theorem to find the Side a (Hypotenuse)
Now, let's solve ~
Therefore, Length of side a is 5 units ~
The answer to this is 384.57909