Part A: c for cost. c=0.31m+0.5
0.31m is the cost per minute. 0.5 is cost per call.
Part B: 0.31m+0.5=5.15 to solve we must rearrange.
subtract 0.5 from each side giving us 0.31m=4.85
divide by 0.31 giving us m=15.65 
 
        
             
        
        
        
1/25 of a minute is 2,4 secs.
1/5 = 2,4s
5/5 = 12 secs
        
                    
             
        
        
        
Answer:
£2.80
Step-by-step explanation:
7%= 7/100
(7/100)*40=2.8
 
        
                    
             
        
        
        
Answer:
The correct answer is the number in the note is 80 and the first digit is 8.
Step-by-step explanation:
Dr. Green finds a note from another scientist. It says how many boxes of bug nets they should bring, but there is a smudge over the first digit of the number.
Number of nets that they must bring is 320.
Each box contains 4 nets.
There number of boxes necessary to be brought is given by  = 80.
 = 80.
Therefore the missing digit of number the number in the note is 8.
 
        
                    
             
        
        
        
Answer:
B. 30
Step-by-step explanation:
A line is 180 degrees, so when we have 100, we subtract that from 180 to get the interior angle of 80.
A triangle has a sum of 180, so we just subtract 80 and 70 from 180 to get 30.
Hope this helps