Question: 1. Each student in a class of 100 reads at least one of mathematics and compu tin g; 67 read mathematics and 44 read both. How many read computing?
2. Each of the 100 students at a music school play at least one instrument, string, woodwind or brass. 70 play a string instrument, 49 woodwind and 49 brass. 20 play both string and woodwind; 25 play string and brass, and 35 play both woodwind and brass . How many play all three types of instrument?