Final answer:
To find the number of boys in the class, we can use the information that there is 1 boy for every 3 girls. By setting up a proportion, we can find the number when 4% of it is known. The number of boys in the class is 15, and 2 times the number is 0.5.
Step-by-step explanation:
To find out how many boys are in the class, we can use the information that there is 1 boy for every 3 girls. Let's denote the number of boys as 'b' and the number of girls as 'g'. We know that b + g = 60, and for every 3 girls there is 1 boy, so g = 3b. Substituting the value of g in the first equation, we get b + 3b = 60, which simplifies to 4b = 60. Dividing both sides by 4, we find that b = 15. Therefore, there are 15 boys in the class.
If 4% of a number is 16, we can set up a proportion to find the number. Let's denote the number as 'n'. Since 4% is equal to 0.04 in decimal form, we can write the proportion as 0.04/n = 16/100. Cross multiplying, we get 0.04 * 100 = 16 * n, which simplifies to 4 = 16n. Dividing both sides by 16, we find that n = 0.25. So the number is 0.25. To find 2 times the number, we simply multiply 0.25 by 2, which gives us 0.5.
Learn more about finding the number of boys in a class and solving proportions