1) x = 2, x = -1/5
2) x = -1, x = 1/4
3) x = 1, x = -1/5
4) x = 5, x = -1/5
5) x =-3, x = 1/3
6) x = -1/4, x = -1/5
7) x = 3/2, x = -1/2
8) x = 1, x = 2
9) x = -1, x = -2
10)None of these
Solution
Put {(3x+1)/(x+1)} = P and reverse 1/P
and solve
we get x = 1 and x = -1/5
Radius of earth is 6400 km. If mass of earth remains conserved and radius of earth would be 1cm and then its density would be (approximately) :-
OPtion
1) 10^26 times the present value of density of earth
2) 10^24 times the present value of density of earth
3) 10^22 times the present value of density of earth
4) 10^20 times the present value of density of earth
5) 10^28 times the present value of density of earth
6) 10^30 times the present value of density of earth
7) 10^8 times the present value of density of earth
8) 10^16 times the present value of density of earth
9) 10^9 times the present value of density of earth
10)None of these
Solution
Since mass is conserved hence
d2/d1 = V1/V2
= R13/R23
= 6400km*6400km*6400km/ 1cm*1cm*1cm
= 6400000m*6400000m*6400000m/0.01m*0.01m*0.01m
= 6.4*6.4*6.4*10^18/10^-6
= 262.144*10^24
approx 2.6*10^26
appro 10^26
After 5 years a man's age will be three times his son's age and 5 years ago he was seven times as old as his son. Find their present ages.
OPtion
1) 60, 15 years
2) 48, 12 years
3) 52, 13 years
4) 44, 11 years
5) 48, 15 years
6) 60, 20 years
7) 40, 10 years
8) 55, 11 years
9) 40, 12 years
10)None of these
Solution
Let present age of father be x and son be y
After 5 years, father's age = 5+x
After 5 years, son's age = 5+y
By the question
(5+x) = 3(5+y) (i)
(x-5) = 7(y-5) (ii)
Solve (i) and (ii)
we get
father's present age = 40 years
and son's present age = 10 years
opiton 7)
ARUN = (A + R + U + N) + 2*(number of letters) = 54 + 8 = 62
MOHIT = (M + O + H + I + T) + 2*(number of letters) = 65 + 10 = 75
UDITA = (U + D + I + T + A) + 2*(number of letters)= 55 + 10 = 65
Similary
NIRAJ = (N + I + R + A + J) + 10 = 52 + 10 = 62
Seven boys are arranged in a row in such a way that
- Ravi is third from Kapil.
- Lakhan and Shyam are together.
- The modulus of difference between the position of Sumit and Ram is 5.
- Geometrical mean of position of Lakhan and Ram is 2.
- Mohan is nearer to Ravi than Kapil.
Arrange all the boys in a correct sequence such that they follow the above written conditions.
Geometrical mean of position of Lakhan and Ram is 2
=> Their positions are necessarily 1st and 4th
Since the modulus of difference between the position of Sumit and Ram is 5
=> Ram is necessarily 1 (if Ram would be at 4th position then it would be difficult to place Sumit)
It is very clear now to say that Sumit is 6th and Lakhan is 4th
Lakhan and Shyam are together
=> Shyam is either 3rd or 5th
If Shyam would be at 5th position then the statement "Ravi is third from Kapil." would be impossible. Therefore it should be 3rd
Ravi and Kapil will take 5th and 7th place
Mohan is at 2nd finally
Since Mohan is nearer to Ravi than Kapil
Therefore Ravi will be 5th.
In a room of dimensions l*b*h = 16*14*12, bricks of dimensions 6*4*2 are placed in such a way that the room is occupied completely. Total number of bricks in a layer on the floor is :-
On the basis of dimensions of brick it is necessary to place the brick in the room in such a way that
l = 4
b = 2
h = 6
( If we place the brick in any other manner then it is not possible to fill the room completely)
Now area of floor = 16*14 = 224
And area of brick = 4*2 = 8
Hence Number of bricks = 224/8 = 28
This is series for no of day in a month starting from January itself.
Jan - 31
Feb - 28
Mar - 31
Apr - 30
May - 31
Jun - 30
Jul - 31
Aug - 31
then
Sep - 30
option 2)
Mathematics has 25%formulas, 25%proofs and apply 25%thinking and 25%efforts.
In real life situations proofs are nothing but already existed stories(we know the solutions from all experienced people).
formulas are nothing but goals. we have so many goals b
K. Mounika
MATHEMATICS is a great motivator for all humans.. Because its career starts with "ZERO" but it never end(INFINITY)..