Terrell needs the total weight of his backpack, water jug, and sleeping bag to be less than 11 kilograms (kg). His backpack weighs 9,300 grams (g), his water jug is 0.45 kg, and his sleeping bag is 25,000 milligrams (mg). Dominic says that the total weight is 34.75 kg. He shows Terrell his math. Backpack: 9,300 ÷ 1,000 = 9.3 kg

Water Jug: 0.45 kg

Sleeping Bag: 25,000 ÷ 1,000 = 25.00 kg

Total:
9.3kg
0.45kg
+25.00kg
34.75kg

a) What mistake did Dominic make?

The math for is wrong because he should have instead of 1,000.

b) Is the total weight of the backpack, water jug, and sleeping bag less than or greater than 11 kilograms? By how many grams?

The total weight of all the equipment is 11 kilograms, by grams.