Answer: 4h/5
Step-by-step explanation:
Assuming that an exponentiation sign is missing, all you need to know is that rational exponents work like this:
![a^{\frac{b}{c}}=\sqrt[c]{a^b}](https://tex.z-dn.net/?f=a%5E%7B%5Cfrac%7Bb%7D%7Bc%7D%7D%3D%5Csqrt%5Bc%5D%7Ba%5Eb%7D)
So, you have

And similarly,
![81^{\frac{7}{4}}=\sqrt[4]{25^7}=\sqrt[4]{(3^4)^7}=3^7](https://tex.z-dn.net/?f=81%5E%7B%5Cfrac%7B7%7D%7B4%7D%7D%3D%5Csqrt%5B4%5D%7B25%5E7%7D%3D%5Csqrt%5B4%5D%7B%283%5E4%29%5E7%7D%3D3%5E7)
Answer:
Step-by-step explanation:
Let the rate of boat in still water be b and the speed of the current be c
- Speed downstream = b + c
- Speed upstream = b - c
<u>We got equations for time:</u>
- 108/(b - c) = 3 ⇒ b - c = 36
- 108/(b + c) = 2 ⇒ b + c = 54
<u>Add up the equations:</u>
- b - c + b + c = 36 + 54
- 2b = 90
- b = 45 km/h
<u>Then finding the values of c</u>
Answer:
the other two angles are 70° and 20°
Step-by-step explanation: