Answer: $15385 should be deposited.
Step-by-step explanation:
The principal was compounded monthly. This means that it was compounded 12 times in a year. So
n = 12
The rate at which the principal was compounded is 7.8%. So 
r = 7.8/100 = 0.078
It was compounded for 4 years. Therefore,
t = 4
The formula for compound interest is 
A = P(1+r/n)^nt
A = total amount in the account at the end of t years. The total amount is given as $21000. Therefore 
21000 = P (1+0.078/12)^12×4
21000 = P (1+0.078/12)^48
21000 = P (1+0.0065)^48
21000 = P (1.0065)^48
P = 21000/1.365
P = $15385
 
        
             
        
        
        
No it is not, whatsoever.
$1 for 2 cups. 14 cups in an afternoon means they got $7. If they did this for three days (7 x 3) they'd have 21 dollars. it is not reasonable because 21 is nowhere near 50.
Hope this helps
        
             
        
        
        
Answer:
Step-by-step explanation:
Order is impotant since you could easily make a positve number negative and vice versa. You switch the order of 5 subtracted by y to y-5.