Question

edna sells mangoes in bags 5-kg and 10-kg. she has a total of 250 kg to sell. If she sells twice as many bags of one than the other, and all the mangoes were sold, how many bags of 10 kg mangoes each are sold?

Answer 1

Since we don't know which sold more, we have to check both

5x+10*2x = 250
10x+5*2x = 250

Only one of these has integer solutions, so that's the one you use.