Are you able to solve these 4 problems from the PISA tests?

Last Tuesday the results of this year’s PISA tests were made public. Spanish students in general did not obtain a good result and it was found that they had lost one and a half mathematics courses. In Catalonia, the situation shown by the results is much worse: almost two years less in reading and a year and a half in mathematics. Below, we propose four of the exercises that the Spanish students had to solve so that you can try to find the correct solution for each of them.