Answer: B) 7.5 hrs Explanation: Let there are L men job requires LK man hours.   job completed in first 4 hrs = L x 4 = 4L job completed in next 4 hrs = 4 x L/2 = 2L job completed in next 4 hrs = 4 x L/4 = L job completed in last 4 hrs = 4 x L/8 = L/2 4L + 2L + L + L/2 = KL K = 7+1/2 = 7.5 hours.

Answer: C) 90 min Explanation: Let X = Time taken for each of Type B Problems(100 Problems)And 2X = Time taken for each of Type A problems(50 problems) Total time period = 3hrs = 3 x 60min = 180 minutes 100X + 50(2X) = 180100X + 100X = 180200X = 180 min X = 180/200X = 0.90 min By convertiing into seconds, X = 0.90 x 60 secondsX = 54 sec So, time taken for Part A problems is = 54 x 2 x 50 = 5400 seconds= 5400/60sec = 90 minutes.

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

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) Rs. 500 Explanation: (kx5x1)/100 + [(1500 - k)x6x1]/100 = 85 5k/100 + 90 – 6k/100 = 85 k/100 = 5 => k = 500

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.

Answer: C) 35 and 11 years Explanation: Let the age of sushma be x and the age of her son is yThen five years before x-5=5(y-5) ...(1)Five years hence x+5 = 3(y+5)-8 .....(2) By soving (1) & (2), we get5y - 15 = 3y + 7y = 11 => x = 35 Therefore, the age of Sushma = 35 and her son = 11.

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.