The average height of A, B and C is 148 cm. If the average height of A and B is 136 cm and that of B and C is 125 cm, then what is the height (in cm) of B?

Let height of A, B and C be $$a,b,c$$ cm respectively.

Average height of A, B and C = $$\frac{(a+b+c)}{3}=148$$

=> $$a+b+c=148\times3=444$$ ------------(i)

Also, average height of A and B = $$\frac{(a+b)}{2}=136$$

=> $$a+b=272$$  ------------(ii)

Similarly, $$b+c=250$$ -----------(iii)

Adding equations (ii) and (iii), => $$a+2b+c=522$$ ----------(iv)

Subtracting equation (i) from (iv), we get :

=> $$b=522-444=78$$

$$\therefore$$ Height of B = 78 cm

=> Ans - (B)