Sum of the ages of 4 men five years ago = 48 x 4
And sum of present ages of the four men = 192 + 5 x 4

Correct Option: D

Sum of the ages of 4 men five years ago
= 48 x 4
=192 yr

And sum of present ages of the four men
= 192 + 5 x 4
= 212 yr

Now ( 212 + Age of the new man ) / 5 = 50
∴ Age of the new man = 50 x 5 - 212
= 38 yr.

a + b + c = 11 x 3 = 33
c + d + e = 17 x 3 = 51
e + f = 22 x 2 = 44
e + c = 17 x 2 = 34
find the value of a + b + c + d + e + f and then average.

Correct Option: D

a + b + c = 11 x 3 = 33 .....(i)
c + d + e = 17 x 3 = 51 .....(ii)
e + f = 22 x 2 = 44 .....(iii)
e + c = 17 x 2 = 34 .....(iv)

From Eqs. (ii) and (iv), we get
34 + d = 51
∴ d = 17

Now adding Eqs. (i), (ii), (v), we get
a + b + c + d + e + f = 33 + 44 + 17 = 94
∴ Average of a, b, c, d, e and f = 94/6 = 15²⁄₃

Average cost =( w₁x₁ + w₂x₂ + w₃x₃ ) / (w₁ +w₂ +w₃)

Correct Option: B

Average cost =( w₁x₁ + w₂x₂ + w₃x₃ ) / (w₁ +w₂ +w₃)

= ( 1200 x 30 +1500 x 25 + 2000 x 32) / ( 1200 + 1500 + 2000 )
= 137500 / 4700
= ₹ 29.25 per kg

Age of A : age of B : age of C= 3 : 5 : 7
So the average age of 3 boys (3x + 5x + 7x ) /3 = 15

Correct Option: A

Age of A : age of B : age of C = 3 : 5 : 7
So the average age of 3 boys (3x + 5x + 7x ) /3 = 15
⇒15x= 15 x 3
∴ x= 3

sum of odd number upto 100 = 1 + 3 + 5 + 7+....+ 95 + 97 + 99
=(1+99) + (3+97) + (5+95) +.... upto 25 terms
= 100 + 100 + 100 +.... upto 25 terms
= 2500

Average = 2500 /50

Correct Option: B

sum of odd number upto 100 = 1 + 3 + 5 + 7+....+ 95 + 97 + 99
=(1+99) + (3+97) + (5+95) +.... upto 25 terms
= 100 + 100 + 100 +.... upto 25 terms
= 2500

Average = 2500 /50
= 50