17. Without using a calculator evaluate. 18. The lengths of three wires were \( 30 \mathrm{~m}, 36 \mathrm{~m} \) and 84 m . Pieces of wire of equal lenght were cat from the three wires. Calculate the least number of pieces obtained.

\( \frac{3}{2}.\frac{1}{4}.\frac{2}{6} \)

\( 0.8 \% \) of 150 is what number?

Dave only plays hockey on Tuesday and Wednesday. Ann only plays hockey on Thursday and Sunday. How many days each week does at least one of them play hockey Ex 8

Ron, Sue and Bob play on the same soccer team. Ron has played 19 minutes in total. Sue has played 15 minutes in total. Bob has played 20 minutes in total. Each pair has played 5 minutes together. All three of them have played at the same time for 3 minutes. How many minutes in total did the team have at least one of them playing.

Para realizar una excursión con 140 alumnos, se han necesitado 4 autobuses. Si para otra excursión hay apuntados 245 alumnos, ¿cuántos autobuses del mismo tipo habrá que contratar?