Find the mean of the first twelve natural numbers. Solution: The first 12 natural numbers are 1, 2, 3, 4, ….12. Mean = sum of observations/total number of observations =... View Article
80 percent of what number is 6? Solution: Let the number be x. Given 80% of x = 6 (80/100)x = 6 => 600 = 80x => x = 600/80 = 7.5 Hence the required number is 7.5.... View Article
A train of length 150 metres takes 10 seconds to pass over another train 100 metres long coming from opposite direction. If the speed of the first train is 30 kmph, the speed of the second train is (a) 72 km/h (b) 60 km/h (c) 54 km/h (d) 48 km/h Solution: Speed of the first train = 30 km/h Let speed of the second train be x km/h... View Article
Shikha’s income is 60% more than that of Shalu. By what percent is Shalu’s income less than Shikha’s? Solution: Let x be the income of Shalu. Shikha’s income is 60% more than that of Shalu Shika’s income = x + (60/100)x = x+ 0.6x... View Article
The factors of x4 + y4 + x2y2 is (a) (x2 + y2)(x2 + y2- xy) (b) (x2 + y2)(x2 - y2) (c) (x2 + y2 + xy)(x2 + y2 - xy) (d) factorisation is not possible Solution: x4 + y4 +... View Article
