Daily Challenge
Tuesday, 20 October 2026
Daily Challenge — 20 October 2026
Three UPSC Prelims-pattern questions — one each from the GS I, GS II and GS III subject areas. Attempt all three before checking your answers.
The Universe and the Earth
At the same instant, the local time at place P is 6:00 a.m. and at place Q is 8:40 a.m. Which one of the following is correct?
Correct answer: A
The time difference is 2 hours 40 minutes, or 160 minutes. Since 1 degree of longitude equals 4 minutes, the longitude difference is 160 / 4 = 40 degrees. Q is ahead in time, so it lies to the east. Option B gets the direction wrong; option C confuses minutes with degrees; option D uses 8 minutes per degree.Regional and Global Groupings
Which one of the following countries is NOT a member of the Shanghai Cooperation Organisation?
Correct answer: D
Turkmenistan follows a policy of permanent neutrality and is not an SCO member. Kazakhstan is a founding member (2001), Pakistan joined with India in 2017, and Iran joined in 2023.Ecology and Ecosystems
Which one of the following best defines a keystone species?
Correct answer: D
A keystone species has an impact far larger than its numbers suggest, as Robert Paine showed with the starfish Pisaster. Option A describes an endemic species, B a flagship species and C an umbrella species.