It will represent a relation. 
How her dogs age relates to its weight.
        
             
        
        
        
Let Jeremy's age be x 
if Jeremy's grandfather is four times as old as he is,grandfather's age is 4x 
if the sum of their ages is 90, we have 
x%2B4x=90 
5x=90 
x=90%2F5 
x=18->Jeremy's age 
Jeremy's grandfather will be 4x=4%2A18=72 
answer: 
D. 72
        
             
        
        
        
In ΔABC, D and E are the midpoints of AB and AC respectively. We know that the ratio of areas of two similar triangles is equal to the ratio of square of their corresponding sides. Hence, the ratio of the areas ΔADE and ΔABC is ar(ΔADE) : ar(ΔABC) = 1 : 4.