Let the original weights of A and B be A and B, respectively. Since the ratio of their weights is 1 : 2, we can say:
A = x and B = 2x
A’s weight increases by 20%, so the new weight of A is:New weight of A = A + 20% of A = x + 0.20x = 1.2x
The total weight of A and B after the increase is 60 kg, and it is also given that the total weight increased by 30%. Therefore, the original total weight of A and B was:
Original total weight = 60/1.30 = 46.15 kg (approximately)
The original total weight of A and B is also A + B = x + 2x = 3x, so:
3 x = 46.15 ⇒ x = 46.15/3 = 15.38 kg (approximately)
So, A’s original weight is approximately 15.38 kg, and B’s original weight is:
B = 2x = 2 × 15.38 = 30.76 kg (approximately)
The new total weight is 60 kg, and the new weight of A is 1.2x = 1.2 × 15.38 = 18.46 kg. Therefore, the new weight of B is:
New weight of B = 60 − 18.46 = 41.54 kg (approximately)
Now, we can calculate the percentage increase in B’s weight:
Thus, B’s weight increased by 35%.