14.86 is the answer to this question
        
                    
             
        
        
        
175 students walk to school. 7+5=12 and 420 divided by 12 is 35. I checked how I did it was correct because of 5*35+7*35=420. Then I found the product of 5*35 which is 175.
        
             
        
        
        
Answer:
area of the BCD triangle=1/2×10×9
 =45
area of the ABD triangle=1/2×10×3
 =15
Total area=45+15
                 =60 square centimetres
 
        
             
        
        
        
The answer is going to be $6.50. hope that helped