SINGAPORE - There are three cards in a bag. One is red on both sides, one is blue on both sides and one is red on one side but blue on the other side. A card is drawn at random and placed on a table. It shows a blue face up. What is the probability that the hidden side is also blue?
In a perfectly functional quad-rotor, what is its maximum upward acceleration?
These are just two of 14 questions plastered over the seats on the upper deck of bus service 96, which runs as a loop service through the National University of Singapore (NUS) from Clementi Bus Interchange.
Designed to challenge tertiary-level students, the questions were crafted by scientists and engineers from Singapore's defence research and development organisation, DSO National Laboratories (DSO).
Accompanying each question is a short profile of the scientist or engineer responsible for it.
Titled #ChallengeInTransit, they cover areas such as physics, chemistry or cyber security.
The questions are meant to raise awareness in the fields of science and engineering and, at the same time, transform a bus ride into a more engaging journey.
In just over a week, close to 100 answers had been submitted online by curious commuters, mostly university students as well as some working adults.
The response had been very encouraging, Ms Serene Tan, DSO's human resource and communications director, told a media briefing on Wednesday (Jan 24).
Some answers included step-by-step workings, showing the thought process of the commuters, said Mr Kenny Wong, head of corporate communications at DSO.
Ms Alisa Loh Hui Ting, a 28-year-old real estate agent, was among those who took up the challenge.
"I thought, why not give it a try, and chose one with a topic I knew about," she said.
She took on question 11 on probability related to the red and blue cards. This question was popular among those who responded, along with another on unmanned aerial vehicles.
Ms Loh described the move to challenge commuters as innovative, saying it encouraged them to think as opposed to listening to music or staring out of the window of the bus.
"Some questions might be tough, but students here are quite smart and I think they would have fun with it if they give it a go," she said.
Commuters have only to tackle one question and submit the answer to curiousbus.sg.
At the end of January, February and March, correct answers would be collated and the winner in each month would receive a portable drone from tech company Hubsan worth more than $100.
Hints and announcements will be shared on DSO's Facebook and Instagram accounts, @dso.sg and @discoverdso.
All solutions will be revealed after the contest ends on March 30.