SOLUTION: The ratio of boys to all students is 2:5. If there are 120 girls, how many are boys.

Algebra ->  Percentage-and-ratio-word-problems -> SOLUTION: The ratio of boys to all students is 2:5. If there are 120 girls, how many are boys.      Log On


   

Question 621321: The ratio of boys to all students is 2:5. If there are 120 girls, how many are boys.
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let b = number of boys
Let g = number of girls
given:
+b%2Fg+=+2%2F5+
+g+=+120+
-----------
+5b+=+2g+
+b+=+%282g%29%2F5+
+b+=+%282%2A120%29%2F5+
+b+=+48+
There are 48 boys
check:
+b%2Fg+=+48%2F120+
+2%2F5+=+48%2F120+
+2%2A24+=+48+
+48+=+48+
OK