Staff Selection Commission Sub Inspector Exam
Question : Directions: Which of the following numbers will replace the question mark (?) in the given series? 5, 20, 60, 240, 720, ?
Option 1: 2580
Option 2: 2880
Option 3: 2160
Option 4: 2675
Correct Answer: 2880
Solution : Given: 5, 20, 60, 240, 720, ?
To get the required missing number in the series, multiply the number by 4 and 3 alternatively – 5 × 4 = 20; 20 × 3 = 60; 60 × 4 = 240; 240 × 3 = 720;
Question : When did Heinrich Hertz discover the photoelectric effect and observe that shining ultraviolet light on the electrodes caused a change in voltage between them?
Option 1: 1916
Option 2: 1902
Option 3: 1990
Option 4: 1887
Correct Answer: 1887
Solution : The correct option is 1887.
In the year 1887, German physicist Heinrich Hertz made a pivotal discovery related to the photoelectric effect while researching radio waves. In the course of his experiments, Hertz utilised a spark gap consisting of two closely spaced, sharp electrodes capable
Question : If $\operatorname{cosec}\theta-\sin\theta=l$ and $\sec\theta-\cos\theta=m$, then the value of $l^2m^2(l^2+m^2+3)$ is:
Option 1: $–1$
Option 2: $0$
Option 3: $1$
Option 4: $2$
Correct Answer: $1$
Solution : Given: $\operatorname{cosec}\theta-\sin\theta=l$ and $\sec\theta-\cos\theta=m$, $l^2m^2(l^2+m^2+3)$ $=(\operatorname{cosec}\theta-\sin\theta)^2(\sec\theta-\cos\theta)^2[(\operatorname{cosec}\theta-\sin\theta)^2+(\sec\theta-\cos\theta)^2+3]$ $= (\frac{1}{\sin\theta}-\sin\theta)^2(\frac{1}{\cos\theta}-\cos\theta)^2[(\frac{1}{\sin\theta}-\sin\theta)^2+(\frac{1}{\cos\theta}-\cos\theta)^2+3]$ $=(\frac{1-\sin^2\theta}{\sin\theta})^2(\frac{1-\cos^2\theta}{\cos\theta})^2[(\frac{1-\sin^2\theta}{\sin\theta})^2+(\frac{1-\cos^2\theta}{\cos\theta})^2+3]$ $=(\frac{cos^2\theta}{\sin\theta})^2(\frac{\sin^2\theta}{\cos\theta})^2[(\frac{\cos^2\theta}{\sin\theta})^2+(\frac{\sin^2\theta}{\cos\theta})^2+3]$ $=(\frac{\cos^4\theta}{\sin^2\theta})(\frac{\sin^4\theta}{\cos^2\theta})[(\frac{\cos^4\theta}{\sin^2\theta})+(\frac{\sin^4\theta}{\cos^2\theta})+3]$ $= \sin^2\theta \cos^2\theta[\frac{\cos^6\theta+\sin^6\theta+3\sin^2\theta \cos^2\theta}{\sin^2\theta \cos^2\theta}]$ $= \cos^6\theta+\sin^6\theta+3\sin^2\theta \cos^2\theta$ $=(\cos^2\theta)^3+\sin^2\theta)^3+3\sin^2\theta \cos^2\theta$ $=(\cos^2\theta+\sin^2\theta)^3-3\cos^2\theta \sin^2\theta(\cos^2\theta+\sin^2\theta)+3\sin^2\theta \cos^2\theta$ $=1^3-3\cos^2\theta \sin^2\theta(1)+3\sin^2\theta \cos^2\theta$ $=1$ Hence, the correct answer is $1$.
Question : The angle between the graph of the linear equation $239x-239y+5=0$ and the x-axis is:
Option 1: 0°
Option 2: 60°
Option 3: 30°
Option 4: 45°
Correct Answer: 45°
Solution : Given: $239x-239y+5=0$ $\therefore$ Slope = $\frac{-239}{-239}$ = 1 So, $\tan\theta= 1=\tan 45°$ $\therefore\theta = 45°$ Hence, the correct answer is 45°.
Question : The average marks of 100 students were initially calculated as 40. Later, it was discovered that a score of 53 was misread as 83. What is the correct average mark after fixing this misread score?
Option 1: 38.7
Option 2: 39
Option 3: 39.7
Option 4: 41
Correct Answer: 39.7
Solution : Given: The average marks of 100 students were found to be 40. It was discovered that a score of 53 was misread as 83. Difference = 83 – 53 = 30 $\therefore$ Final average = 40 – $\frac{30}{100}$ = 39.7 Hence, the correct answer is
Question : If a shop-keeper purchases cashew nuts at Rs. 250 per kg and sells them at Rs. 10 per 50 gm, then he makes a:
Option 1: 25% loss
Option 2: 25% profit
Option 3: 20% profit
Option 4: 20% loss
Correct Answer: 25% loss
Solution : Given in question, the cost price (CP) of 1000 gm of cashew nut = Rs. 250 So, CP of 50 gm of cashew nut = $\frac{250}{1000}$ × 50 = Rs. 12.5 The selling price (SP) of 50 gm of cashew nut = Rs. 10
Question : Directions: In the following question, choose the correct alternative which will improve the part of the sentence given in quotes.
Some children are much more "aggressive then" others.
Option 1: 1
Option 2: 2
Option 3: 3
Option 4: 4
Correct Answer: 2
Solution : The correct choice is the second option.
Explanation: The phrase aggressive then should be replaced with aggressive than to convey the intended meaning that some children display a higher level of aggression as compared to others. Than is used for comparison, and then
Question : What is the name of the app launched by the Union Ministry of Power to provide real-time information sharing on power supply?
Option 1: Urja Mitra
Option 2: BHIM
Option 3: Urja
Option 4: UMANG
Correct Answer: Urja Mitra
Solution : The correct option is Urja Mitra.
The Union Ministry of Power has introduced the Urja Mitra app. This comprehensive platform includes a mobile application, a web portal, and a central hub for state power distribution utilities. It provides real-time updates on the power supply.
Question : One of the ______, the giant redwood tree Sequoia, is one of the tallest tree species.
Option 1: mosses
Option 2: pteridophytes
Option 3: liverworts
Option 4: gymnosperms
Correct Answer: gymnosperms
Solution : The correct answer is gymnosperms.
One of the gymnosperms, the giant redwood tree Sequoia, is one of the tallest tree species. Gymnosperms are a group of seed-producing plants that include conifers like the Sequoia. Renowned for their immense height, these trees exemplify the grandeur
Question : In which month of 1915 did Mahatma Gandhi finally return from South Africa after his successful agitation against the racist regime?
Option 1: July
Option 2: May
Option 3: January
Option 4: March
Correct Answer: January
Solution : The correct option is January
Mahatma Gandhi returned from South Africa to India in January 1915 after successfully leading campaigns against racial discrimination. His efforts, marked by nonviolent resistance, contributed to social change and laid the foundation for his later role in India's struggle for
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