Class 12th

An alcohol solution is formed by mixing two solutions. Solution 1 had a concentration of 20 percent and a volume of 3L while solution 2 had a concentration of 40 percent with a volume of 1L. The resultant solution was named solution 3. Three litres of solution 4 which had an unknown concentration was mixed with solution 3. What must be concentration of solution 4 if that the new resultant solution has a concentration of 50 percent?

Two geometric means a, b are inserted between x and y such that a³ + b³ = n (ab) A, where A is the arithmetic mean of x and y. What is value of n?

A square with maximum possible length of the side is inscribed in an equilateral triangle and a circle of maximum possible radius is inscribed in the square. Find the ratio of the length of equilateral of the equilateral triangle to the radius of circle.

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R.

Assertion A: The potential ( $V$ ) at any axial point, at 2 m distance ( $r$ ) from the centre of the dipole of dipole moment vector $\dot{P}$ of magnitude, $4*10^{-6}Cm$ , is $\pm 9*10^3 V$ .

(Take $\frac{1}{4\pi {ϵ}_0}=9*10^9$ SI units)

Reason R :  $V=\pm \frac{2P}{4\pi {?}_0{r}^2}$ , where $r$  is the distance of any axial point, situated at 2 m from the centre of the dipole.

In the light of the above statements, choose the correct answer from the options given below:

A certain sum of money invested at CI becomes Rs 3380 in 2 years & Rs 3515.20 in 3 years. What is the sum invested & what is rate % per annum?

Duronto Express in motion, 66 metre long overtakes a passenger train 88 metres long travelling at 30 kmph in the opposite direction in 0.168 minute. Find speed of the Duronto Express.

A 10 floor building is build by 2 men, 3 women and 4 boys in 10 days. If a man, a women & a boy work in the ratio 5 : 4 : 2. Find the time that 6 men, 4 women and 7 boys take to build a 16 floor building.

During the months of October Krishna went to a temple every day. He offered 4 flowers to her favourite deity. At the end of the month, he noticed that he did not offer the same combination of flowers on any two days during the month. What is the minimum number of varieties of flowers offered by Krishna during the month? 

In a quiz, six team with two member one man and one woman each participated. During dinner all the 12 members were seated around a round table. Find the probability that no man sat to the left of the woman from this team, provided that men and women were alternatively seated.