 
<translate> Bari X ya zama shekarun Cooper. Don haka Dante yana da shekaru X * 2 kuma Maria tana da shekaru X * 2 + 1. Jimlar shekarun Cooper, Dante, da Maria shine X + (X * 2) + (X * 2 + 1) = 31. Idan muka haɗa abubuwa iri ɗaya, za mu sami X*5+1=31. Idan muka cire guda daga bangarorin biyu, za mu samu X * 5 = 30. Idan muka raba bangarorin biyu da 5, sai mu samu cewa x = 6 shekara. Amsar ita ce: 6. <eng> Let X be the age of Cooper. So Dante is X * 2 years old and Maria is X * 2 + 1 year old. The sum of Cooper’s, Dante’s, and Maria’s ages is X + (X * 2) + (X * 2 + 1) = 31. Combining like terms, we get X * 5 + 1 = 31. Subtracting one from both sides, we get X * 5 = 30. Dividing both sides by 5, we get X = 6 years old.
The answer: 6. 