Answer : 1. "20 kg"
Explanation :

Let's denote the weight of A as 𝑥x kg and the weight of B as 𝑦y kg.

Given:

1. 𝑥+𝑦=80x+y=80 (Sum of weights of A and B is 80 kg)
2. 0.5𝑥=56𝑦0.5x=65y (50% of A's weight is 5665 times the weight of B)

We can solve these two equations to find the values of 𝑥x and 𝑦y, and then calculate the difference between their weights.

From equation 2: 0.5𝑥=56𝑦0.5x=65y Multiply both sides by 2 to get rid of the fraction: 𝑥=56𝑦×2x=65y×2 𝑥=106𝑦x=610y 𝑥=53𝑦x=35y

Now substitute this expression for 𝑥x into equation 1: 53𝑦+𝑦=8035y+y=80 83𝑦=8038y=80 Multiply both sides by 3883: 𝑦=80×38y=80×83 𝑦=30y=30

Now that we have found the weight of B, we can find the weight of A using equation 1: 𝑥+30=80x+30=80 𝑥=80−30x=80−30 𝑥=50x=50

So, the weight of A is 50 kg and the weight of B is 30 kg.

Now, let's find the difference between their weights: Difference=Weight of A−Weight of BDifference=Weight of A−Weight of B Difference=50−30Difference=50−30 Difference=20Difference=20

Therefore, the difference between their weights is 20 kg.