Out of 1200 pupils in a school, 900 are boys and the rest are girls. If 20% of the boys and 30% of the girls wear spectacles,find:
a.how many pupils in wear spectacles
b.what percent of the total number of pupils wear spectacles.
A, is 270 and
B is 22.5%
1050
To find the answers to these questions, we need to calculate the number of boys and girls who wear spectacles and then add those numbers together to find the total number of pupils who wear spectacles.
a) First, let's calculate the number of boys who wear spectacles. Since 20% of the boys wear spectacles, we can find this by multiplying the total number of boys (900) by 0.2:
Number of boys wearing spectacles = 900 * 0.2 = <<900*0.2=180>>180.
Next, let's calculate the number of girls who wear spectacles. Since the rest of the pupils are girls, we can find this by subtracting the number of boys from the total number of pupils:
Number of girls = Total number of pupils - Number of boys = 1200 - 900 = <<1200-900=300>>300.
Since 30% of the girls wear spectacles, we can calculate the number of girls wearing spectacles by multiplying the number of girls by 0.3:
Number of girls wearing spectacles = 300 * 0.3 = <<300*0.3=90>>90.
Now, we can find the total number of pupils wearing spectacles by adding the number of boys wearing spectacles to the number of girls wearing spectacles:
Total number of pupils wearing spectacles = Number of boys wearing spectacles + Number of girls wearing spectacles = 180 + 90 = <<180+90=270>>270.
b) To find the percentage of the total number of pupils wearing spectacles, we divide the number of pupils wearing spectacles by the total number of pupils (1200) and then multiply by 100:
Percentage = (Number of pupils wearing spectacles / Total number of pupils) * 100 = (270 / 1200) * 100 = 22.5%.
Therefore, 270 pupils in the school wear spectacles, which is approximately 22.5% of the total number of pupils.
(a) .20*900 + .30*300
(b) divide that by 1200