There are 50 students in classroom A. Two fifths learn piano. One fifth of those who learn piano wear spectacles. How many learn piano but do not wear spectacles?
Isabella learns 1 new word every Monday, 2 every Tuesday, 3 every Wednesday, and so on up to 7 every Sunday. Starting on Monday, on which weekday will she learn the 90th word?
A rectangle's breadth is increased by 50%. By what percentage should its length decrease so that the area is unchanged? Round to the nearest whole percent.
A pie chart shows how Primary 6 students travel to school. The train sector is $88^\circ$ and the bus sector $140^\circ$. If 110 students travel by train, how many travel by bus?
In the diagram, $CDEF$ is a square, $E$ is the midpoint of $DG$, $AD=2DC$, and $\angle ABC$ and $\angle ADG$ are right angles. If $\angle BAG=105^\circ$, find $\angle BCA$.
Ken, Ronald and Wendy each make two statements about whether the food is fries, burger, pie or hotdog. One person makes two true statements, one makes one true and one false, and one makes two false statements. What is the food?
In a 200-m race, when Usain finished, Yohan was 20 m behind and Nickel was 36 m behind Yohan. At constant respective speeds, how far was Nickel from the finish when Yohan finished?