Product of two co-prime numbers is 117. Then their L.C.M. is
Rs 3
Rs 39
Rs 117
Rs 9
Answer : Option C.
HCF of two prime numbers =1
∴ Product of numbers = HCF * LCM
LCM = 117
The diameters of two circles are the side of a square and the diagonal of the square respectively. The ratio of the areas of the smaller circle and the larger circle is
√2 : √3
1 : √3
1 : 2
1 : 4
Answer : Option C.
Side of square = x units
Diagonal of square =√2x units
Radius of smaller circle =x/2 units
Radius of larger circle =√2x/2=x/√2 units
⇒ Required ratio of areas = π(x2/4).π(x2/2)
= 2 : 4 = 1 : 2
The total surface area of a sphere is 8π square unit. The volume of the sphere is
(8√3)π cubic unit
(8√3/5)π cubic unit
(8√2/3)π cubic unit
(8/3) π cubic unit
Answer : Option C.
Surface area of sphere = 4πr2 ⇒ r2 = 2 ⇒ r ⇒√2 units
⇒ Volume of sphere
=(4/3)πr3=(4/3)π * (√2)3=(8√2/3)πcubic units
A conical flask is full of water.The flask has base radius r and height h. This water is poured into a cylindrical flask of base radius mr. The height of water in the cylindrical flask is
(2h)/m
h/(3m2)
m/(2h)
(h/2).m2
Answer : Option B.
Volume of water in conical flask =(1/3)πr2h
If the height of water level in cylindrical flask be H units, then πm2r2H =(1/3)πr2h
⇒H=(1/3).((πr2h)/(πm2r2))= h/(3m2)
A and B together can complete; a piece of work in 12 days, B and C can do it in 20 days and C and A can do it in 15 days. A, B and C together can complete it in
8 days
10 days
12 days
6 days
Answer : Option B.
(A+B)’s 1 day’s work = 1/12
(B+C)’s 1 day’s work = 1/20
(C+A)’s 1 day’s work = 1/15
On adding all there, 2(A+B+C)’s day’s work = (1/12)+(1/20)+(1/15)=1/5
⇒(A+B+C)’s 1 day’s work = 1/10
Hence, the work will be finished in 10 days.
A and B together can complete a work in 3 days. They start together. But, after 2 days, B left the work. If the work is completed after 2 more days. B alone could do the work in
6 days
8 days
10 days
4 days
Answer : Option A.
(A+B)’s 2 day’s work = 2/3
Remaining work = 1- (2/3)= 1/3
Time taken by A in 1/3 doing work = 2 days
Time taken by A in completing the work = 6 days
B’s 1 day’s work = (1/3)-(1/6)= 1/6
B alone will complete the work in 6 days
A does 20% less work than B. If A can complete a piece of work in 15/2 hours, then B can do it in
6 hours
8 hours
10 hours
4 hours
Answer : Option A.
Efficiency of A and B = 4 : 5
Ratio of respective time = 5 : 4
⇒Time taken by B = (4/5)*(15/2)= 6 hours
The number of ways in which letters of the word PRAISE be arranged
500
1200
200
700
Answer : Option A.
Let the prices of school bag and shoes is 7x and 5x.
Given that 7x - 5x = 200 ⇒ 2x = 200 ⇒ x = 100.
So the price of a pair of shoes = 5x = 5 * 100 = 500
A sum of Rs. 300 is divided among P, Q and R in such a way that Q gets Rs. 30 more than P and R gets Rs. 60 more than Q. The ratio of their share is
3 : 2 : 5
2 : 5 : 3
5 : 3 : 2
2 : 3 : 5
Answer : Option D.
Q = P + 30 ⇒ Q – P = 30 and R – Q = 60 = 2 × 30
⇒Required ratio = 2 : 3 : 5
Look : 3 – 2 = 1, 5 – 3 = 2