Answer: Tanu weighs 27.25kg.
Explanation:
In this problem, we have to undergo a simple addition and subtraction.
We know that: Anu's weight is 31kg and 250g, which translates to 31.25kg and we are aware that Manu's weight is 39kg and 500g, which translates to 39.5.
In order to find our answer: We must add the weight of these two friends, 39.5kg+31.25kg = 70.75kg then subtract it by the total of 98kg to find the missing friend's (Tanu) weight. In doing so, we receive an answer of: 98kg - 70.75kg = 27.25kg