Rohan and Amit can build a tank in 12 days while Amit and Sohan in 15 days and Rohan and Sohan in 20 days. How long would each take to do the same work? find how long each do

38+105= 143, 39+104=143, and you will find then adding the numbers on opposite sides, moving inwards yields the answer 138 every time. because of this, you’re going to multiply 138 times the number of pairs, which is 34. therefore, 34*138= 4692(i’m sorry if it’s the wrong numbers, but it’s the right concept)