Let The total number of workers = N
According To the question,
60N = 12 x 400 + 56 (N - 12)

Correct Option: B

Let The total number of workers = N
According To the question,
60N = 12 x 400 + 56 (N - 12)
⇒ 60N - 56N = 4800 - 672
⇒ 4N = 4128
∴ N = 1032

Here, n₁ = 5, n₂ = 10, n₃ = 15, a₁ = 25, a₂ = 50, a₃ = 35
According to the formula,
Average price = (n₁a₁ + n₂a₂ + n₃a₃) / (n₁ + n₂ + n₃)

Correct Option: A

Here, n₁ = 5, n₂ = 10, n₃ = 15, a₁ = 25, a₂ = 50, a₃ = 35
According to the formula,
Average price = (n₁a₁ + n₂a₂ + n₃a₃) / (n₁ + n₂ + n₃)
= (5 x 25 + 10 x 50 + 15 x 35) / (5 + 10 + 15)
= (25 + 100 + 105) / (1 + 2 + 3)
= 230/6
= ₹ 38.33

Given that, number of boys (n₁) = 15
Numbers of girls (n₂)= 10
Average weight of boys and girls = 38.4 kg
Average of boys = 40 kg
Let average of girls be a₂
By formula, average = (na₁ + n₂ a₂) / (n₁ + n₂)

Correct Option: C

Given that, number of boys (n₁) = 15
Numbers of girls (n₂)= 10
Average weight of boys and girls = 38.4 kg
Average of boys = 40 kg
Let average of girls be a₂
By formula, average = (na₁ + n₂ a₂) / (n₁ + n₂)
⇒ 38.4 = (15(40) + 10 x a₂)/(15 + 10)
⇒ 38.4 x 25 = 600+ 10a₂
⇒ a₂= (960 - 600)/10 = 360/10 = 36 kg

Here n = 120, a = 35, x = 39, y = 15
Number of students passed = n (a - y)/(x - y)

Correct Option: B

Here n = 120, a = 35, x = 39, y = 15
Number of students passed = n (a - y)/(x - y)
= 120(35 - 15)/(39 -15)
= 100 students passed

If two equal distance are covered at different speeds at A km/h and B km/h respectively, then
Average speed during the whole journey = 2AB/(A + B) km/h

Correct Option: E

If two equal distance are covered at different speeds at A km/h and B km/h respectively, then
Average speed during the whole journey = 2AB/(A + B) km/h

∴ Average speed of the car = (2 x 42 x 48) / (42 + 48)
= (2 x 42 x 48)/90
= 44.8 km/h