A class has 42 pupils. The ratio of the number of boys to the number of girls is 5 : 2. Find the number of boys in the class.
My understanding is that in order to find the number of boys, you need to find BOTH genders first, and so I could only get up to the number of GIRLS, which I did: 42 divided by 2 = 21
42 divided by 5 = 8.4
But now I'm stuck...
Please help and see if my understanding is correct...
boys : girls = 5:2
So, if there are 5x boys, there are 2x girls
5x+2x = 42
x = 6
Now what do you say?
So basically the number of boys is 6?
And so is girls??
NO!
I solved for the value of x.
Now go back and read what I said about the number of girls and boys.
Ohhhh I get it
So 5x = 5 x 6 = 30 (BOYS)
And 2x = 2 x 6 = 12 (GIRLS)
So the number of boys is 30 yes?
that's better.
Consider a "group" of students to be 5 boys and 2 girls.
x is the number of such groups in the class.
5×5×5×1030
Your understanding is partly correct. To find the number of boys, you need to find the total number of parts in the ratio (5 + 2 = 7 parts) and then divide the total number of pupils by the total number of parts.
Here's how you can proceed:
1. Find the number of girls:
- Divide the total number of pupils (42) by the total number of parts in the ratio (7):
42 ÷ 7 = 6
- So, the number of girls is 6.
2. Find the number of boys:
- Multiply the number of girls by the ratio value for boys (5 parts):
6 × 5 = 30
- So, the number of boys is 30.
Therefore, there are 30 boys in the class.
Let me know if there's anything else I can help you with!