Deon's gas tank is (1)/(3)
full. after he buys 2
gallons of gas, it is (1)/(2)
full. how many gallons can deon's tank hold?

let's say it holds "x" gallons of gas.

how much is 1/3 of that?  well is just (1/3)x.

how about 1/2 of that?  well is just (1/2)x.

we know that

notice, we simply multiplied both sides by the LCD of all fractions, to just do away with the denominators.

Here's what we know that we can put into an equation.
⇒The number of nickels mutliplied by .05 and the number of dimes multiplied by .1 equal 5.00.
⇒2n=d; that means that the number of nickels times 2 equals the number of dimes.
Let's solve:
We can use substitution with out two equations.
0.05n+0.10d= 5.00
2n=d
We can put the second equation in as the value of n in the first equation.
0.05n+0.10(2n)=5.00
Now solve till d has a value.
0.05n+0.2n=5.00
0.25n=5.00
5.00÷0.25=20=n
There are 20 nickels. If there are 20 nickels, there has to be 40 dimes since he has twice as many dimes as nickels. Let's check this with the other equation.
0.05(20)+0.1(40)
1+4=5
So, there are 20 nickels and 40 dimes.
Tell me if this helps!!