Weight (Mass) • Topic 5 of 5

Word Problems

Word problems are where weight meets real life: adding the shopping, sharing a load, working out cost from a per-kilogram price. The reliable method has three steps. First, make all the units the same, usually grams or all kilograms, before doing any arithmetic, because mixing 1 kg 250 g with 750 g directly is the number-one error. Second, pick the right operation: 'in all' or 'total' means add, 'how much more' or 'left' means subtract, 'each' or 'per kg' points to multiply or divide. Third, convert the answer back into a sensible unit (3500 g is usually better written as 3 kg 500 g). Shopping problems lean on price-per-kilogram: if mangoes cost 60 rupees per kg, then 1/2 kg costs 30 rupees and 250 g costs 15 rupees, found by scaling the price down in the same proportion as the weight. A typical exam item chains two of these ideas, for instance adding three packets, then subtracting what was used, or buying 2 kg 500 g at a per-kg rate. Slow, unit-matched working beats clever shortcuts here.

✅ Solved examples

1. A bag holds 2 kg 500 g of sugar and another holds 1 kg 750 g. What is the total weight?
Convert to grams: 2500 g + 1750 g = 4250 g = 4 kg 250 g. Always match units before adding.
2. From a 5 kg packet of flour, 1 kg 800 g is used. How much flour is left?
5 kg = 5000 g; 5000 g - 1800 g = 3200 g = 3 kg 200 g remaining.
3. Apples cost 80 rupees per kilogram. What is the cost of 1/2 kg (500 g)?
Half a kilogram costs half the per-kg price: 80 / 2 = 40 rupees. So 500 g of apples cost 40 rupees.
4. A shopkeeper sells 250 g packets of tea. How many full packets can be made from 2 kg of tea?
2 kg = 2000 g; 2000 / 250 = 8 packets. Each kilogram gives 4 packets of 250 g, so 2 kg gives 8.

✏️ Practice — try these, take hints as needed

1. Three parcels weigh 1 kg 200 g, 800 g and 1 kg 500 g. Find their total weight.
Change everything to grams first.
Add 1200 + 800 + 1500.
3500 g = 3 kg 500 g
2. Rice costs 50 rupees per kg. What is the cost of 250 g?
250 g is one-fourth of a kilogram.
Take one-fourth of 50.
12.50 rupees
3. A watermelon weighs 4 kg 250 g and a muskmelon weighs 1 kg 750 g. How much heavier is the watermelon?
Subtract in grams.
4250 minus 1750.
2500 g = 2 kg 500 g
4. How many 200 g packets of spice can be filled from 3 kg of spice?
Convert 3 kg to grams.
Divide 3000 by 200.
15 packets

📝 Topic test — 8 questions

Auto-graded with full solutions; saved to your dashboard. Use the calculator and formula sheet (top-right) any time.

Loading questions…
← Practical Weight Measurement Take the chapter test →