so first u have to make all fractions involved into fractions with common denominators.
this makes it easier to deal with
then u get
intial amount of pennies: 7/10
pennies left after removing 240: 1/2×5/5=5/10.
then you get that the difference of 240 pennies is a difference of 2/10 by doin the following calculation:
7/10-5/10=2/10
then you find the value of 1/10 pennies =240/2=120
then u can get the capacity of the piggy bank which is 10/10 by mjltiplying 1/10 value by 10
which is 120×10=1200 pennies