SOLUTION: A jar is filled with $1 and $2 in the ratio 5 to 4. There are 30 $1 coins in the jar. How many coins are there in total?

Algebra ->  Equations -> SOLUTION: A jar is filled with $1 and $2 in the ratio 5 to 4. There are 30 $1 coins in the jar. How many coins are there in total?      Log On


   

Question 1194190: A jar is filled with $1 and $2 in the ratio 5 to 4. There are 30 $1 coins in the jar. How many coins are there in total?
Answer by greenestamps(13198) About Me  (Show Source):
You can put this solution on YOUR website!


Given the ratio 5:4, you can set up a proportion

5%2F4=30%2Fx

to find the number of $2 coins.

If you solve that by the standard method seen in most textbooks, you would "cross multiply" to get

5x=120
x=120%2F5=24

A less formal and much easier way to solve the proportion is simply to see that 30 is 6 times 5, so the number of $2 coins is 6 times 4, which is 24.

Finally, you could use formal algebra, starting with the given ratio 5:4

5x = # of $1 coins
4x = # of $2 coins

5x=30
x = 30/5 =6
4x = 4(6) = 24