Answer: B) 2 : 1 Explanation: Given that train K crosses a pole in 30 seconds and train L crosses the same pole in one minute and 15 seconds. Let the length of train K be Lk and that of train L be Ll given that Lk = 3/4 Ll As the train K and L crosses the pole in 30 seconds and 80 seconds respectively, => Speed of train K = sk = Lk/30 Speed of train L = sl = Ll/80 Lk = 3/4 Ll => sk = 3/4 Ll/(30) = Ll/40 Ratio of their speeds = sk : sl = Ll/40 : Ll/80 => 1/40 : 1/80  =  2 : 1

Answer: B) 2 Explanation: Given that x = 2+ 223 + 213   So x - 2 = 223 + 213   Now cubing on both sides, we get     => x3-8-6x2+12x = 4 + 2 + 6(x-2)   Therefore, x3-6x2+6x = -6 + 8 = 2

Answer: A) 288 sq.cm Explanation: Length of the thread is 36 cms. length wise twice breath wise once then totally thrice.so 36/3 = 12.so length is 12 x 2 = 24 cmsbreath is 12 cmsArea of the book = length x breath = 24 x 12 = 288 sq.cm

Answer: A) Heart Explanation: Arteries carry oxygenated blood away from the heart to the tissues, except for pulmonary arteries, which carry blood to the lungs for oxygenation (usually veins carry deoxygenated blood to the heart but the pulmonary veins carry oxygenated blood as well).

Answer: A) phosphates and sugars Explanation: In DNA, adjacent nucleotides are linked by a phosphodiester bond: a covalent bond is formed between the 5' phosphate group of one nucleotide and the 3'-OH group of another.   Hence, in this manner, each strand of DNA has a "backbone" of phosphate-sugar-phosphate-sugar-phosphate.

Answer: C) Ram Nath Kovind Explanation: BJP-led NDA's presidential candidate Ram Nath Kovind registered an emphatic win over his rival and Opposition candidate Meira Kumar. Succeeding Pranab Mukherjee, Kovind sworn in as the 14th president of India on July 25, 2017.

Answer: A) Microsoft Explanation: Microsoft has acquired Flipgrid, an education start-up with an app that lets students record and share videos on specific topics with their classmates.   Microsoft is making Flipgrid free of charge.

Answer: C) 20 to 45 degrees Celsius Explanation: The Bacteria that causes Food Borne illness are called Food Borne Pathogens. Most of the pathogens are mesophilic in nature, optimum temperature may be around 20-45 degree celsius. This range of temperatures is often called the "Danger Zone." Dry foods do not support the growth of bacteria.   In order to kill pathogenic bacteria you need temperatures above 74ºC. Temperature is the easiest factor to control in order to prevent bacterial growth.