Answer: D) Methane Explanation: Methane is the main component of biogas and natural gas.

Answer: B) 8 : 13 Explanation: To get the solution that contains 1 part of milk and two parts of water,they must be mixed in the ratio as7x+6x/5y+11y = 1/226x = 16yx/y = 16/26x/y = 8/13

On carefully inspecting this question, one can understand that there are two days which are important and these are: A. My Birthday. B. The day when I am making this statement. If you think for a while, you will understand that such statements can be made only around the year’s end. So, if my birthday is on 31 December, then I will be making this statement on 1 January. I will further explain using the following example: 1. Consider that today is 01 January 2017. 2. Then, the day before yesterday was 30 December 2016 and according to the question I was 25 then. 3. Yesterday was 31 December 2016, which happens to be my birthday too (Woohoo!), and my age increases by one to become 26. 4. I will turn 27 on my birthday this year (31 December 2017). 5. I will turn 28 on my birthday next year (31 December 2018). Now, if you read the question again, it will make more sense:   The day before yesterday(30 December 2016), I was 25 years old and next year(31 December 2018) I will be 28.

Answer: B) 30 min Explanation: Distance travelled by Ramu = 45 x 4 = 180 km Somu travelled the same distance in 6 hours. His speed = 180/6 = 30 km/hr Hence in the conditional case, Ramu's speed = 45 - 9 = 36 km/hr and Somu's speed = 30 + 10 = 40km/hr. Therefore travel time of Ramu and Somu would be 5 hours and 4.5 hours respectively. Hence difference in the time taken = 0.5 hours = 30 minutes.

Answer: B) 30 years Explanation: Let Karan’s present age be x years and Shiva’s present age be y years.Then, according to the first condition,x - 10 = 3(y - 10) or x - 3y = - 20 ..(1) Now, Karan’s age after 10 years = (x + 10) yearsShiva’s age after 10 years = (y + 10)(x + 10) = 2 (y + 10) or x - 2y = 10 ..(2) Solving (1) and (2), we get x = 70 and y = 30Karan’s age = 70 years and Shiva’s age = 30 years.

Answer: B) Rs.17,500 Explanation: Let’s assume John bought the laptop for Rs. 100He then sells it to Mark at a loss of 20% => Rs. 80,Who consequently sells it to Kevin at a profit of 25% =>  Rs. 100Then, Kevin sells it back to Mark for Rs. 90 (Rs.4.50 for every Rs. 5 that he had paid initially), so he suffers a loss of Rs. 10Therefore, for Rs. 100 there is a loss of Rs. 10,Then for Rs. 1,75,000 there will be a loss of Rs. 17,500.

Answer: A) 1 Explanation: Only one such symbol is there in the given arrangement. It is 4@5.

Answer: D) Leather bags Explanation: Biodegradable substances can be broken down into simpler, harmless substances in nature with due course of time by the biological process such as action of microbes. They can be recycled as a part of food chain.   Here, Leather bags are biodegradable.