Q101 of 140 Page 196

The strength of a school is 2000. If 40 % of the students are girls then how many boys are there in the school?

Given, the strength of school = 2000

percentage of girls in school = 40%

percentage of boys in school = 100 – 40 = 60%

Number of boys in school = 60% of 2000 = × 2000

= 60 × 20 = 1200

What percent of Rs 80 is Rs 100?

100

45% of the population of a town are men and 40% are women. What is the percentage of children?

102

Chalk contains 10% calcium, 3% carbon and 12% oxygen. Find the amount of carbon and calcium (in grams) in kg of chalk.

103

800 kg of mortar consists of 55% sand, 33% cement and rest lime. What is the mass of lime in mortar?