The right answer is Option A.
Step-by-step explanation:
Let, 
x be the postcards
y be the large envelops
According to given statement; 
14x+5y=12   Eqn 1
10x+15y=24.80   Eqn 2
Multiplying Eqn 1 by 3;

Subtracting Eqn 2 from Eqn 3;

Dividing both sides by 32

Putting x=0.35 in Eqn 1;

Dividing both sides by 5

Therefore, one large envelope costs $1.42
The right answer is Option A.
Keywords: linear equations, subtraction
Learn more about linear equations at:
#LearnwithBrainly
 
        
             
        
        
        
Answer:
7.5
Step-by-step explanation:
If there are 2 bottles and 15 cups then...  
15 ÷ 2 = 7.5  
He poured 7.5 cups of water in each bottle. 
diagram?? maybe you could do this...
 
        
                    
             
        
        
        
I did this before and the answer is b
        
             
        
        
        
Answer:
4989600
Step-by-step explanation:
The given word is MATHEMATICS
Number of letters in the given word is 11
there are 2 M's, 2 A's and 2 T's
the given word is arranged in 11! ways
three letters are repeating, so we divide by repeating occurrences
number of different arrangements =
= 4989600
 
        
             
        
        
        
A and b can do a piece of work in 12 days. If a alone have to finish the job among b and c so 
A and b=12
A (24 days alone without b)
So if b and c 15 days and c 20 days. If a have to do all I would add 24 and 15 and 20 which would be 59 days