Question 1184437
.
Lucy's penny bank is {{{cross(3\10)}}}  3/10 full. After she adds 560 pennies, it is 4/5 full. 
How many pennies can Lucy's bank hold?
~~~~~~~~~~~~~~~~~


<pre>
Let x be the number of pennies making the bank full.


Then

    {{{(4/5)x}}} - {{{(3/10)x}}} = 560


Multiply everything by 10

    8x - 3x = 5600

       5x   = 5600

        x   = 5600/5 = 1120.


<U>ANSWER</U>.  1120 pennies make the bank full.
</pre>

Solved and thoroughly explained.