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?
1). 56
2). 78
3). 112
4). 130
Average height of A, B, & C = 148
So, A + B + C = 148 × 3 = 444 ----(1)
Average height of A & B = 136
So, A + B = 136 × 2 = 272 ----(2)
Average height of B & C = 125
So, B + C = 125 × 2 = 250 ----(3)
Subtract equation (2) from equation (1)
A + B + C – A – B = 444 – 272
⇒ C = 172
Putting value of C in equation (3), we get
B + 172 = 250
∴ B = 250 – 172 = 78 cm