(1) 39 minutes (2) 46 minutes (3) 40 minutes (4) 45 minutes Solution: Part of the tank filled by pipes A and B in 1 minute = 1/36+1/45= 5+4/180 = 9/180 = 1/20 Part of the tank filled by these pipes in 7 minutes =7/20 Remaining unfilled part = 1-7/20= 20-7/20= 13/20 When all three […]
(1) 100 (2) 92 (3) 91 (4) 50 Solution: Number of digits from 1 to 9 = 9Number of digits used in writingfrom 10 to 50= 41 x 2 =82:. Total digits =82 + 9 = 91 Then Option is (3) 91
How many digits in all are required to write numbers from 1to 50? Read More »
(1) 15 (2) 60 (3) 36 (4) 45 Solution: If the numbers be 3x and 4x, then their LCM = 12x =12x= 180⇒x=225/15=15 =First number = 3x = 45 ⇒Then the option is (4) 45
Two numbers are in the ratio 3 : 4 and their LCM is 180. The first number is Read More »
(1) 136 square cm. (2) 120 square cm. (3) 125 square cm. (4) 100 square cm. Solution: Let the length, breadth and height of the parallelopiped be a, b and c cm respectively. :. a+ b+ c= 20 2 (ab + bc + ca) = 264 :. (a+b+c)2= a2+b2+c2+2(ab + bc+ ca) ⇒400= a2+b2+c2+264 ⇒a2+b2+c2=
Solution: Let the last number be x.According to the question,18 x 10 + 11 x 20 + x= 30 x 15⇒ 180 + 220 + x = 450⇒400 +x= 450 ⇒x=450-400=50 Then the answer is 50
(1)16 (2)18 (3) 19 (4) 12 Solution: ⇒When we divide 1000 by 225.quotient = 4⇒When we divide 5000 by 225.quotient = 22:. Required answer = 22 – 4 = 18 ⇒Then the option is (2) 18
How many numbers between 1000 and 5000 are exactly divisible by 225 ? Read More »
(1) 24 km/hr. (2) 36 km/hr. (3) 40 km/hr. (4)45 km/hr. Solution: ⇒Suppose length of train be x According to question x+50/14= x/10 ⇒ 14x = 10x+500 ⇒ 4x= 500 ⇒ x= 500/4=125m Therefore, speed = 125/10*18/5= 45kmph
made the mistake of dividing the fraction by 6/7 and so got an answer which exceeded the correct answer by 13/70. Find the fraction- (1) 2/3 (2) 3/5 (3) 4/5 (4) 7/9 Solution: Let the fraction = x According to the question : 6/7 of x = x/6/7 – 13/70 ⇒ 6x/7 = 7x/6-13/70 ⇒7x/6-6x/7
A boy on being asked what 6/7 of a certain fraction was, Read More »
(1) 7 (2)19 (3) 82 (4) 84 Solution : If each number is multiplied by a certain number, then the average is also multiplied by that number. = Requires average = 7*12=84 Then option is (4) 84
(1) 45 Minutes (2) 50 Minutes (3) 60 Minutes (4) None of these Solution: 5/3 of usual 3/5 of usual time as he reaches earlier. = 3/5 usual time + 20 Minutes= Usual time 20 minutes = (1-3/5) usual time = 2/5 usual time Usual time = 20*5/2= 50 Minutes Then answer is 50 minutes.
