Answer: 40

Explanation:
Let the number of group a employees be m. The number of group b employees be m -10
(m-10)/m = (4800-4000)/(4000-3000) = 0.8 and m = 50

Answer: 56

Explanation:
Total of the 11 numbers= 11*50 =550
Total of the first six numbers = 6*49 = 294
The total of the list six numbers=6 * 52 = 312

Therefore the Sixth number = 294 + 312 – 550 = 56

Answer: Cannot be determined

Explanation:
As we don’t know the percentage of profit at which he sold the rice, we cannot determine the average cost price. Hence the required ratio cannot be determined.

Answer: 68

Explanation:
Quantity of milk in 20 lts = 0.6 * 20 = 12 lts
Upon addition of 5 lts of pure milk, the new solution of 25 lts would contain 17 lts of milk.
Percentage of milk = (17/25) (100) = 68%

Answer: 42

Explanation:
Let the average of six players=x ,Average of seven players = x + 10
Sum of scores of six players = 6x
(6x + 112)/7 = x +10 =>x = 42

Answer: 85

Explanation:
The no of girls in the class are 60.
Total marks of the boys = (30)(75) = 2250
Total marks of the girls = (5)(60) = 5400
Total marks of the class = 7650
Average marks of the class in the test = 7650/90 = 85

Answer: 110kg

Explanation:
∑X / n = ∑X / 40
Let A  = weight of new student
X_new   = X + 0.25
∑X_new = ∑X – 100 + A
(X + 0.25)40 = (X)40 – 100 + A
40X + 10 = 40X – 100 + A
A = 110 kg

Answer: 13 years 4 months

Explanation:
X1 = 12 N1 = 50
X2 = 15 N2 = 40
= (X1 N1 + X2 N2) / N1 + N2
(50 × 12) + (15 × 40) / 50 + 40
= 600 + 600 / 90
= 1200 / 90
=13 1/3 years
=13 years 4 months

Answer: 3:4:5

Explanation:
Let the required proportion be x:y:z
(10x+12y+18z) / x+y+z = 14
Going by the options, we have only choice (2) satisfying the above equation.

Answer: Rs 500

Explanation:
Cost of 12 horses= 12(250) = Rs 3000
Cost of remaining 18 horses = Rs 9000
Average cost of eighteen horses = 9000/18 = Rs 500