Answer:
160 minutes
Step-by-step explanation:
Find out how many minutes are in a hour. 60 min in one hour. 60 x 2 = 120
120 + 40 = 160
4+4 is 8 so 4+5 is 9.So the strategy is a double +1. That is the strategy.
It is known that any exponential function with the form f(x)=a^x is an increasing function while a function of the form g(x)=a^(-x) is a decreasing function.
Furthermore, it a function h(x) is increasing, then the function -h(x) is decreasing. By analogy, if a function k(x) is decreasing, then -k(x) is increasing.
Now let's analyze the functions from the problem.

Since (6/7)^x is increasing and the multiplying factor of 10 is positive, then the function <em>f(x)</em> is also increasing.
Use these rules to find whether each function is increasing or decreasing.
Remember that increasing functions are used to represent growth while decreasing functions are used to represent decay.
No x = -10 cannot be an input value because the x is the number of students , which can only be from 0 and above. You cannot have negative students.
Answer:
an angle with 90 degree is a right angle