New Learning Composite Mathematics SK Gupta Anubhuti Gangal Class 7 Percentage and Its Applications Self Practice 8E Solution
(1) Ravi’s class has 19 boys and 12 girls. What is its percentage composition?
(2) Chalk contains 10% calcium, 3% carbon and 12% oxygen. Find the amount of carbon and calcium (in grams) in 2 and 1/2 kg of chalk.
(3) An alloy contains 4% tin, 1% zinc and the remaining copper.
(a) What is the percentage composition of the alloy?
(b) Find the mass (in kg) of each metal in 5 tonnes of the alloy.
(4) A packet of cake mix has the composition of its contents shown on the label. Calculate the percentage composition of the cake mix.
Nutritional value (per 50 g serve) | |
Protein |
3.5 g |
Fat |
5.5 g |
Carbohydrates |
27 g |
Other ingredients |
14 g |
(5) The average composition (by weight) of milk is shown in the table.
(a) How many grams are there of each component in 1 kg of milk?
(b) How many grams of proteins are there in 7.5 kg of milk?
Ingredients |
Percentage |
Carbohydrate |
5 |
Protein |
3 |
Fat |
4 |
Water |
87 |
Other |
1 |
Solution All: