proportion problem and solution

Sagot :

if there are 5 boys in the classroom every 6 girls how many boys are there if there are 25 girls
Solution:     5:6=N:24
                   5 x 24=120
                   6/120=20 boys
The ratio of two numbers is 2:5. If the larger number is 25, what is the smaller number?
2:5 = n:25
2 (25) = 50
50 ÷ 5 = 10
2:5 = 10:25
To check, multiply the means and the extremes. It must be equal.
5(10) = 2 (25)
    50  = 50
Therefore, the answer is 10.

Three numbers have a ratio of 1:2:3. If their sum is 30, find the value of the largest number. 
1 : 2 : 3 = 30
1 + 2 + 3 = 6
30 ÷ 6 = 5

5 (1) = 5
5 (2) = 10
5 (3) = 15

1:2:3 = 5:10:15


Therefore, the answer is 15.

Those are just two examples of problems regarding proportion. I hope it help. ☺