Is it normal for a 10months baby to drink only 100ml every 3hrs? Is it too little? Solids will be 2-3 times and each time 2-3 table spoon.

Is your baby taking any extra liquids or filling up on anything else? Juice, snacks etc? As long as this isn't so, then your baby will eat and drink the right amount they need - as little as ithe is. I would suggest offering the milk first and then the food. Your baby would still be getting all his or her nutritional needs from milk so it's more important that you offer that before the solids.