Step-by-step explanation:

0<r<6
the least number of ride he can go on is 0 which is none and the most is 6 because 15/2.50=6
Answer:
(x + 7)(x + 3).
Step-by-step explanation:
x^2 +10x + 21
21 = 7 * 3 and 10 = 7 +3
so the factors are
(x + 7)(x + 3).
The speed of wind and speed of plane in still air are 23 and 135
km/h respectively.
<u>Step-by-step explanation:</u>
Let the speed of wind and speed of plane in still air are w and p km/h respectively.
The effective speed on onward journey was
................(1)
The effective speed on return journey was
..............(2)
Adding equation (1) and equation (2) we get,
⇒ 
⇒ 
⇒ 
Putting value of
in
we get:
⇒ 
⇒ 
⇒ 
Therefore ,The speed of wind and speed of plane in still air are 23 and 135
km/h respectively.