[PaulZe]

why do you need all the algebra. you know from the from the question that c has to be 4 greater than r. What 2 numbers add up to 10 where one number is 4 greater than the other. the answer is 7 and 3. So C is 7 and R is 3. since c is 7...d has to be 17 to add up to 24. Add all 3 together and you get 27...easy peasy
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[noiseman]

why do you need all the algebra. you know from the from the question that c has to be 4 greater than r. What 2 numbers add up to 10 where one number is 4 greater than the other. the answer is 7 and 3. So C is 7 and R is 3. since c is 7...d has to be 17 to add up to 24. Add all 3 together and you get 27...easy peasy

Yep, I did something similar. Was easy to figure out in my head without resorting to algebra.