40 students are in the science club. 45% are girls. New girls enter the club and now the percentage of girls is 56%. How many new girls join the club?
10 girls
10
10
To find out how many new girls joined the science club, we can follow these steps:
Step 1: Let's first find the initial number of girls in the science club. We know that initially, 45% of the 40 students are girls. So, we can calculate the initial number of girls by multiplying the total number of students (40) by the percentage of girls (45%) and dividing it by 100.
Initial number of girls = (45/100) x 40 = 18 girls.
Step 2: Now, let's find the final number of girls in the science club. We know that after new girls joined the club, the percentage of girls is 56%. We need to find the number of girls that represents 56% of the total number of students.
Let's assume the number of new girls is 'x'. So, the total number of girls becomes 18 (initial girls) + x (new girls).
We can set up the following equation based on the above information:
(18 + x) / 40 = 56 / 100
Step 3: Now, let's solve the equation to find the value of 'x':
(18 + x) / 40 = 56 / 100
Cross-multiplying, we get:
(18 + x) x 100 = 56 x 40
1800 + 100x = 2240
100x = 2240 - 1800
100x = 440
x = 440 / 100
x = 4.4
Since the number of girls cannot be a decimal value, we can round it to the nearest whole number. Therefore, approximately 4 new girls joined the science club.
45% of 40 is 18
after x girls join,
(18+x)/(40+x) = 56/100
Now just find x