Sample Aptitude Questions of L&T ECC

Given: 8 women = 6 Men = 12 Boys
∴ 12 Men + 12 Women + 12 Boys
= 12 Men + 9 Men + 6 Men = 27 Men
We have, M₁ = 9, D₁= 6, t₁ = 6, W₁ = 1
M₂ = 27, D₂ = ?, t₂ = 8, W₂ = 1
∴ M₁D₁T₁W₂ = M₂D₂T₂W₁
⇒ 9 × 6 × 6 × 1 = 27 × D₂ × 8 × 1
=> D₂ = 3/2 days or, 1¹⁄_2.

x₁, x2,  x₃ ,. . . .. x_n   =  nx...............(1)

Now,according to 1st condition we have 

x₁, x2,  x₃ ,. . . .. x_n  + 50/ n+1 =  x+1

x₁, x2,  x₃ ,. . . .. x_n   =  (n+1)(x+1) - 50..............(2)

Further,according to 2nd condition we have

 x₁, x2,  x₃ ,. . . .. x_n  + 50+50/ n+2 =  x+1.5

x₁, x2,  x₃ ,. . . .. x_n   =  (n+2)(x+1.5) - 100..............(3)

Solving (1) and (2), we get
x + n = 49…………….. (4)
Solving (1) and (3), we get
4x + 3n = 194  ……………. (5)
Now, Solving (4) and (5), we get
n = 2, x = 47
So, the original average weight (in kg) of the class = 47
Alternate Solution :
Let x be the original average and n be the number of students.
From the first increase in the average,
we get 50 – x = n + 1
From the second increase in the average,
we get 100 – 2x = 1.5 (n + 2)
Solving, we get the value of x = 47.