An explorer finds four islands connected by six bridges. He wants to visit A, B, C and D in that order, then return to A. How many different routes can he take?
During a field trip, class 5A is divided into groups, each containing either seven girls or four boys. At the end, the teacher asks some whole groups to line up. Which number CANNOT be the number of students in the line?
A grocery store has jars of sweets. One eleventh of all jars contain macarons. One tenth of the remaining jars contain cookies. The 18 jars left contain jelly beans. How many jars are there altogether?
Alice leaves home at 15:00 and cycles to a friend’s house at 6 km/h, arriving at 15:20. She stays for 45 minutes, then cycles home along the same route at 8 km/h. When does she get home?
Mike has five identical grids, each small cell being a square of side 1 cm. He shades parts of the grids as shown. Find the total shaded area in all five figures.
Seven students, Alice, Ben, Cindy, Dan, Erik, Fred and Grace, take a mathematics test. Their scores appear in the chart, but the names are missing. Find Erik’s score, given that:
- Alice’s and Grace’s scores differ by 1.
- Grace scores 4 less than Cindy.
- Cindy scores 3 more than Ben.
- Dan’s score lies between Ben’s and Fred’s scores.
- Cindy’s score is either the highest or the lowest.
Peter finishes a mathematics book and an English book in one month. The table records how many pages he reads each week. In the last week he reads one fourth of the entire mathematics book. How many pages are in the English book?
A box contains 6 red, 8 green, 10 blue, 12 yellow and 15 white balls. Suzy draws without looking and wants at least 3 red and at least 2 green balls. What is the smallest number she must draw to be certain?
Four friends travel together and take photographs. Each friend appears in either 4 or 5 photos, and every photo contains exactly 3 of the friends. How many photos did they take?