The sum of the ages of a group of children is 36. In 2 years the sum of the ages will be 60. How many children are in the group?
There are 12 children
A full glass container of liquid weighs 400 g. When empty it weighs 100 grams. How much does it weigh when it is half full?
It weighs 250 g.
Rodolfo has many coins, all the same. To buy one apple and a pear he pays 5 coins; to buy a banana and a apple he pays 7 coins; to buy a pear and a banana he pays 10 coins. How many coins does he pay for an apple, a pear and a banana?
11 coins