let x be the correct answer and y be the wrong answer
so the total number of questions is (x + y) = 150.....(1)
=> 4x - 2y = 420.....(2)
By solving (1) & (2), we get
=> 6x = 720
hence x = 120
Therefore, number of correct answers are 120.

Suppose Sweety is sitting between Rohan and Karthik such that she is to the right of him.....then as Raju is opposite to Rohan then Raju must be to the left of Karthik.

We know that,

One square meter is equal to 10,00,000 sq mm.
Given, each mesh is 8mm length and 5mm wide
Therefore for each mesh : 8 x 5 = 40 sq mm.
So, number of meshes = 100000040 = 25000.

Since they can do 19 programs in 19 hours, Then 52 programs in 52 hours respectively.
And a 15 min interval
Total time they take to do 52 programs is 52 hours 15 minutes.

Let us assume A is the faster and B is slower, A takes 10s to finish a lap of 50 m, B takes 17s(approx) to finish a lap of 50 m.
So at 11th sec A starts his 2nd lap by the time B will be in between so that is the first time they will meet each other, at 21st sec A starts his 3rd lap by the time B will be coming back to finish his 2nd lap. So that is the second time they meet in opposite. Then at 31st sec A will start his 4th lap by the time B would not even finish 2nd lap as he take 34(2*17) sec to finish 2 laps. So at 35th sec B will start his 3rd lap by the time A will be coming back to finish his 4th lap in the half way so they will meet 3rd time. At 41st sec A will start its fifth lap by the time B will be going to finish 3rd lap in same direction. At 50th second both will complete A's 5th lap and B's 3rd lap. So they will start next lap(A's 6th and B's 4th) from the same point in same direction. And A will finish the race after completing 300m(6*50) total distance and then they wont meet opposite to each other.

So totally they met 3 times in opposite direction.

Given ratio of number of sheep and horses = 4 : 15
Let number of sheep and horses are 4k and 15k
Number of horses = 13200/110 = 120
Now 15K = 120 and k = 8
Number of sheep = 4k = (4 x 8) = 32

Let the smaller number be k.
Then, larger number = (3355 + k)
Therefore 3355 + k = (6k + 15)
‹=› 5k = 3340
‹=› k = 668.

Therefore, the smaller number k = 668 and now the larger number = 3355+668 = 4023.

In one day work done by K = 1/20

Work done by K in 2 days = 1/10

Work done by K,L,M on 3rd day =1/20 + 1/30 + 1/60 = 1/10

Therefore, workdone in 3 days is = 1/10 + 1/10 = 1/5

1/5th of the work will be completed at the end of 3 days.

The remaining work = 1 - 1/5 = 4/5

1/5 of work is completed in 3 days

Total work wiil be done in 3 x 5 = 15 days.