In the P.E. lesson, 45 students form two lines: boys in one line and girls in the other. The girls’ line has 9 more students than the boys’ line. How many girls are there?
Paul surveys every student in his class about their favourite pet. The numbers on the vertical scale were accidentally erased. If 9 more students choose dogs than cats, how many students are in the class?
Every day in May, Julia either runs for 30 minutes or swims for 20 minutes. During the month she spends 9 hours running. How many minutes does she spend swimming?
Eight students place eight identical square papers bearing their names, one after another, to make the picture shown. Cindy places hers eighth. Who places theirs fifth?
A box contains 13 red, 15 blue, 18 green and 14 white marbles. Lucy draws without looking. What is the least number she must draw to guarantee at least one marble of every colour?