20% is the same as saying 0.2, so if you multiply 0.2 by 240, you should get your answer. Or an alternate way of seeing it is 2 times 24.
        
             
        
        
        
Answer:
10
Step-by-step explanation:
 
        
             
        
        
        
Step-by-step explanation:
A left Riemann sum approximates a definite integral as:

Given ∫₂⁸ cos(x²) dx:
a = 2, b = 8, and f(x) = cos(x²)
Therefore, Δx = 6/n and x = 2 + (6/n) (k − 1).
Plugging into the sum:
∑₁ⁿ cos((2 + (6/n) (k − 1))²) (6/n)
Therefore, the answer is C.  Notice that answer D would be a right Riemann sum rather than a left (uses k instead of k−1).
 
        
             
        
        
        
Answer:
a and b.
Step-by-step explanation:
I’ll explain by giving an example.
Let’s say that: a=3;b=4;c=5; => they all are consecutive -> their sum is 12.
=> if we use a) n=3 => 3*n+3=3*3+3=12 => correct.
b) n+(n+1)+(n+2)= 3+4+5=12=> correct.
c)n+2n+3n=3+6+9=18=>incorrect.
d)3n=3*3=9=>incorrect.