In a house, there are dogs, cats and parrot in the ratio 3:7:5. If the number of cats was more than the number of dogs by a multiple of both 9 and 7. What is the minimum number of pets in the house?  Choose the correct choice from the following: A) 945 B) 630 C) 252 D) 238 E) None of these
Explanation :   Let, the number of Dogs, Cat and Parrots be 3k, 7k and 5k respectively.   Then, According to the question,   =&gt;7k−3k=63p. (where p is any positive integer).   As the number is a multiple of both 9 and 7, it has to be multiple of 63.   =&gt;k=63p/4.   Minimum value of p for which k is a natural number is 4.   Thus, k=63.   Hence, the number of pets are (63x5) + (63x3) + (63x7) i.e 315 +189+ 441= 945.   945nswer : 945
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In a house, there are dogs, cats and parrot in the ratio 3:7:5. If the number of cats was more than the number of dogs by a multiple of both 9 and 7. What is the minimum number of pets in the house?